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Violaceae


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 © Flora Nordica

edited by Thomas Karlsson (TK)
and Thomas Marcussen (TM),
co-authors Peter Wind (PW)
and Bengt Jonsell (BJ).
Author species 1, 6–8, 18–22 TM,
species 2–5, 10–17 PW,
species 9 BJ.
(6a, 20080501)

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Viola edited by Thomas Marcussen (TM) and Thomas Karlsson (TK); species 1, 6–8, 18–22 by T. Marcussen, species 2–5, 10–17 by Peter Wind (PW), species 9 by Bengt Jonsell (BJ). Version 5 (080430)

This treatment is partly outdated - the final version is available in print (Flora Nordica 6, Jonsell & Karlsson 2010).

Viola L.

Linnaeus, Sp. pl.: 933 (1753).

Literature. Becker 1910a, 1910b, 1925a, Clausen 1929, Ballard et al. 1998, Marcussen & Borgen 2000.

Annual or perennial herbs. Leaves in rosettes at the rhizome apex and/or along lateral stems or stolons, petiolate, with stipules; stipules entire, dentate, fimbriate, pinnate or palmate, sometimes large, green and leaf-like; blade entire with cordate to cuneate base and crenulate to serrate margin.
Flowers single in leaf axils, drooping, bisexual, zygomorphic, often cleistogamous; pedicel with two bracteoles. Sepals 5, lanceolate, persistent in fruit, each with a distinct appendage (appendage length measured in the direction of the sepal). Petals 5, obovate, blue to violet, sometimes yellow or white (or a combination), sometimes some or all with dark streaks (nectar guides); the lowermost petal spurred, lateral petals usually with a tuft of hyaline hairs at the throat. Stamens 5, barely protruding from throat, the lowermost two each with a nectariferous appendage projecting into the spur; anthers connivent, with an apical, scale-like extension of the connective. Ovary superior, unilocular, with 3 placentas and numerous ovules. Style barely protruding from throat, often geniculate near the base, often ± widened towards the apex and sometimes papillose, in some groups narrowed to a ± hooked beak; stigma sunken in a cavity at the apex of the style (at the apex of the beak, if present). Cleistogamous flowers usually with only one, rudimentary petal (the lowermost one), lower 2 stamens with a single pollen sac each, upper 3 developed as staminodia. Fruit a trigonous or globose capsule (if trigonous opening loculicidally with 3 keeled, coriaceous valves, if globose disintegrating at maturity). Seeds ovoid or elliptical, with elaiosome.
Chromosome base-numbers x=7, x=6, and secondarily x=10 and x=12 (section Viola); polyploidy and aneuploidy. Diploids to octoploids in Norden.
Morphological characters. Within Viola, the mode of growth differs conspicuously between species groups. The basic structure, at least in the groups represented in the North-Temperate region, is a monopodial rhizome with a terminal leaf rosette (with leaves in several rows) and lateral annual flowering shoots (with leaves in two rows). This basic structure, present e.g. in V. biflora and V. riviniana, has been modified in several ways. In some species the terminal leaf rosette has been secondarily lost and the shoot system is sympodial with annual flowering shoots arising from a branched rhizome (e.g. V. canina, V. stagnina). In other species the lateral aerial stems have been modified to creeping stolons (e.g. V. palustris, V. odorata) or have been lost altogether (e.g. V. selkirkii, V. hirta). In sect. Melanium the original shoot system is highly modified and not readily recognizable.
Species having most or all flowers on leafy stems are termed caulescent, whereas those producing flowers from the leaf rosettes or from stolons are referred to as acaulescent. Species with a terminal leaf rosette are said to be rosulate whereas those lacking a terminal rosette are called arosulate.
Subdivision of the genus. The genus comprises ca 500 species and is widely distributed in temperate areas in the northern hemisphere and in S America, with centres of diversity in SE Europe, E Asia and S America; isolated endemics occur in Africa (equatorial high mountains and the Cape), E Australia, Tasmania, New Zealand and Hawaii. Becker (1925) divided the genus into 14 sections, of which the north-temperate section Nomimium Ging. (correctly referred to as sect. Viola) is the largest. Its 17 infrasectional groups were originally unranked but have later usually been treated as subsections.
Tentative phylogenies (with particular emphasis on the north-temperate groups), based on general morphology, chromosome numbers and crossing experiments, have been proposed (Gershoy 1928, Clausen 1929, Miyaji 1929). A more recently presented phylogeny, constructed from ITS sequence variation (Ballard et al. 1998, Ballard & Sytsma 2000), contradicts the earlier hypotheses in several respects. However, Marcussen et al. (in prep.) demonstrate, with data from three single-copy nuclear genes and the chloroplast, that the inconsistencies largely result from concerted evolution among ITS loci (leading to uniparental inheritance of the marker) acting in combination with reticulate, allopolyploid evolution and poor resolution near the basal nodes. Also the recently presented phylogeny shows a basal split-off of the South American and Australian sections, consistent with the idea that the genus had its origin in the southern hemisphere (Clausen 1929).
The Nordic taxa fall into three major groups, coinciding with the traditionally accepted sections Chamaemelanium s.lat., Melanium and Viola s.lat. Section Chamaemelanium is diploid (x=6) and morphologically diverse, with a mainly amphipacific distribution. Section Melanium is polyploid but with widespread aneuploidy; it has few representatives outside the Mediterranean region. Section Viola s.lat. is allopolyploid with secondary base-numbers x=10, 11, 12, 13 and occurs with numerous taxa throughout the North-temperate region. The latter two sections are, despite their striking morphological dissimilarity, closely related and apparently originated through hybridization between the Chamaemelanium and another as yet unidentified lineage.
Awaiting a conclusive phylogeny of the genus, a conservative and wide delimitation of infrageneric taxa (supported however by preliminary phylogenetic data) is adopted here. It mainly follows Becker's (1925) treatment but, as recommended by Clausen (1964), sect. Dischidium is included in sect. Chamaemelanium. – The following six sections and subsections are recognized in the Nordic flora.
Sect. Chamaemelanium Ging. subsect. Biflorae J.C. Clausen (syn. sect. Dischidium Ging.; x=6). Perennial, yellow-flowered species, mostly caulescent and with inconspicuous stipules. Style not papillose, with two lobes at the apex; stylar orifice lateral between the lobes (not at the apex of a rostrum). Mainly in eastern Asia. – Includes species 1 (V. biflora).
Sect. Melanium Ging. (aneuploid, base chromosome number not unambiguously established; see Erben 1996, Yockteng et al. 2003, Hildebrandt et al. 2006). A rather homogeneous section comprising both perennials and annuals; Nordic taxa caulescent and with large, more or less divided stipules. Flowers blue, yellow or a combination of blue, yellow and white. Cleistogamous flowers not present. Style apex strongly widened, in front view almost rectangular, bordered with papillae, without a beak but with a wide stigmatic cavity and, below this, with a ± triangular flap. Mainly in southern Europe, with many local endemics. Hybrids usually fertile. – Includes species 2–5 and the rare casuals V. lutea and V. ×williamsii.
Sect. Viola subsect. Adnatae W. Becker (syn. sect. Violidium (K. Koch) Juz.; x=12). Perennial, rosette-forming, without stolons. Stipules distinctly adnate to the petiole. Style apex flattened, edged beneath and on the sides; stylar orifice at the tip of a distinct beak. Mainly eastern Asia. – Includes species 6 (V. selkirkii).
Sect. Viola subsect. Stolonosae Kupffer (x=12, 22). Perennial, acaulescent, usually stoloniferous. Stipules inconspicuous, free. Style apex flattened, edged beneath and on the sides; stylar orifice at the tip of a distinct beak. Mainly circumboreal. – Includes species 7–8 (V. epipsila and V. palustris) and the rare casual V. lanceolata.
Sect. Viola subsect. Rostratae Kupffer (syn. sect. Trigonocarpea Godr.; x=10). Perennial, usually caulescent, with free and often conspicuous stipules (V. uliginosa is acaulescent and has adnate stipules). Style ± cylindrical, often papillose towards the tip, gradually narrowed into a slightly bent beak. North-temperate. – Includes species 9–17. In spite of its morphological distinctness, V. uliginosa belongs naturally within subsect. Rostratae (see Taxonomy under V. uliginosa).
Section Viola subsect. Viola (syn. sect. Uncinatae Kupffer; x=10). Perennial, acaulescent, usually stoloniferous. Stipules free, usually hyaline. Style ± cylindrical, at the apex distinctly hooked, not papillose. Capsules globose, inexplosive, lying on the ground. Hybrids often somewhat fertile. Eurasia. – Includes species 17–22.
Biology. Cleistogamy occurs in most groups of the genus, and in most Nordic taxa, but not in section Melanium (see above) and apparently not in V. uliginosa (species 13). The cleistogamy is seasonal, developing in response to light and temperature (Mayers & Lord 1983a, Redbo-Torstensson & Berg 1995). Chasmogamous, insect-pollinated flowers are produced in spring or early summer, and cleistogamous, obligately self-pollinating ones later in the season (during the brief transitional period it is not rare to find intermediate flowers which are usually self-pollinating). The fertilization of the chasmogamous flowers in spring is often unsuccessful, mainly due to a lack of pollinators, but this is compensated for by increased production of cleistogamous flowers (Redbo-Torstensson & Berg 1995). In southeastern Norway the early-flowering V. collina, V. odorata and V. suavis have considerably lower pollination success than the later-flowering V. hirta (Marcussen et al. 1997).
Seeds derived from chasmogamous flowers are often larger and heavier than seeds from cleistogamous flowers (Eckstein & Otte 2005), up to almost twice as heavy in V. odorata (Marcussen et al. 1997). Where studied there was no noticeable negative effect of inbreeding (Culley 2000), indicating that the lower germination rate and plantlet size found in the cleistogamously derived progeny of some species (Berg & Redbo-Torstensson 1999) likely result from flower type differences rather than from genetic differences.
Although Viola pollen is not sticky (which is the rule in insect-pollinated genera) but smooth, most Nordic species seem to be dependent on visits by pollinators for full seed-set; the exception is Viola arvensis, which regularly self-pollinates.
Usually, the pollen is kept within the cavity between the ovary and the apical appendages of the anthers (the pollen sacs open inwards). At this time the style has already emerged through the apex of the cone formed by the anther appendages. In this phase the pollen is available for long-tongued and medium-tongued nectar-seeking insects like honeybees, bumblebees, solitary bees and beeflies (Beattie 1971). Later on, pollen is shed onto the spurred petal, becoming available for generalist pollinators like hoverflies, or for eventual delayed selfing (e.g. Mattila & Salonen 1995, Culley 2002).
In sect. Melanium the pollen is not withheld by the anther appendages but is deposited at the base of the spurred petal, in a groove which is bordered by a thick rim of hairs.
In cleistogamous flowers of subsect. Viola, pollination occurs as a result of pollen tubes penetrating the wall of the undehisced anther sac and growing to the stigmatic cavity nearby (Mayers & Lord 1983b); in other groups, preliminary observations suggest that pollen is simply released in close proximity of the recurved style.
The capsules are usually trigonous and borne on erect pedicels. The sutures of the capsule are greatly thickened by hygroscopic sclereids. At maturity the capsule springs open and the seeds are forcefully ejected, typically 1–5 meters. The seeds have a small elaiosome and are carried further by ants. In subsection Viola (species 18–22) the ability to disperse seeds ballistically has been secondarily lost, and seed dispersal relies solely on ants. In this group the pedicels are bent downwards at maturity; the capsules are large and globose, lie on the ground and are often gnawed open by ants. The seeds are larger than in the other species and have white, much larger and more conspicuous elaiosomes (Beattie & Lyons 1975).
Vegetative propagation is either by branching of the rhizome or in some cases persistence of the lateral stems (often resulting in the formation of fairly dense clones, e.g. V. hirta and V. rupestris), by long runners (resulting in the formation of loose but wide clones, e.g. V. palustris and V. odorata), or by adventitious bud formation on the roots (resulting in apparently independent ramets, e.g. V. canina, V. mirabilis, V. riviniana and V. stagnina).
Having mycorrhiza may be supposed to be the rule in the genus. Arbuscular mycorrhiza occurs in all Viola groups represented in Norden, and probably in all species (documented at least in V. biflora, V. elatior, V. mirabilis, V. riviniana and V. tricolor).
Chromosome numbers. Polyploidy is pronounced in Viola, and it was from this genus that the first example of an intrageneric polyploid series was reported (Miyaji 1913). Of the three large north-temperate groups, sect. Chamaemelanium is diploid with chromosome numbers based on x=6, sect. Melanium is aneuploid and polyploid, and sect. Viola is allotetraploid (Nordal & Jonsell 1998, Marcussen & Nordal 1998) with secondary base-numbers of x=10–13 depending on subsection.
Secondary allopolyploidy, based on these tetraploid numbers, occurs within section Viola. In subsect. Stolonosae (x=12), V. palustris (EEXX) may have arisen from a hybrid between V. epipsila (EE) and another unknown species (XX) (Kuta 1989). In subsect. Rostratae (x=10), the V. stagnina genome (SS) may have been involved in the origin of the allopolyploids V. pumila (SSYY) and V. canina (SSCC). The x=10 taxa having YY and CC are not known; however the latter seems to have hybridized also with V. reichenbachiana (RR) to give rise to V. riviniana (CCRR) (Moore & Harvey 1961, Valentine 1962). In subsect. Viola, the alpine V. pyrenaica (PP) appears to have been involved in the formation of V. suavis (PPZZ) (Marcussen & Borgen 2000). V. canina, V. mirabilis and V. rupestris seem to have been involved in the origin of other allopolyploids in southern Europe.
The chromosome base-number x=6 found in sect. Chamaemelanium was long held to be the base number also of the entire genus. However, recent counts on taxa from one basally offsplitting lineage (Sanso & Seo 2005) suggest x=7 as an equally likely number. For the Violaceae as a whole x=8 seems probable.
Hybridization. Hybridization between species within the same subsection is common, especially between species that share one or more genomes (see above); such hybrids can be abundant, at least locally. Other within-subsection hybrids may be rare or absent because the parental taxa rarely meet and/or intermediate habitats do not occur, but also genetic differences may play a role. In crossing experiments with species from subsect. Rostratae, crosses between secondary diploids (2n=20) were, on the whole, less successful than crosses involving more polyploid taxa (Valentine 1962). Incidentally, hybrids between secondary diploids appear to be rare also under natural conditions. Intersubsectional hybrids are on the whole extremely rare and have never been reported from Norden, although at least some are fairly easily synthesized and vigorous (Gershoy 1928, Marcussen unpublished data).
The hybrids are sterile or have strongly reduced fertility, except in sect. Melanium (Valentine 1962). They are usually vegetatively vigorous and can form large stands, even crowding out their parents. Due to the high degree of sterility, introgression and formation of hybrid swarms appear to be rare, in Norden at least.
Hybridization is usually associated with transitional habitats affected by human activity, and especially areas subjected to changes in land use.
Identification. The species should as a rule be easy to identify since they have good diagnostic characters (except, to some degree, V. riviniana versus V. reichenbachiana and V. palustris versus V. epipsila). Major complicating factors are (1) the frequent ocurrence of hybrids, (2) the geographical variation in some species (e.g. V. hirta), and (3) the plasticity of some species (growing outside their normal habitat they may be conceived as transitional to some related species).
A critical step in determining a deviant plant is therefore to find out whether it is a hybrid or not. In the many cases where hybrids are sterile this is not too difficult. In sterile plants the cleistogamous summer flowers wither without forming capsules (rarely a small, few-seeded one). Aborted cleistogamous flowers, as well as valves of mature capsules, usually remain on the dead shoots from the previous year, and therefore even vernal specimens (with chasmogamous flowers only) can as a rule be classified.
When a plant has been recognized as a hybrid it is usually fairly easy to determine at least one of its parents. Because most or all hybrids are primary hybrids they are more or less intermediate (or slightly closer to the more polyploid parent in cases of hybridization between species on different ploidy levels). Nevertheless, a series of characters are dominantly inherited in hybrids and are thus particularly useful for their correct determination, i.e. the absence of terminal rosette (subsect. Rostratae), scentless flowers (subsect. Viola) and stolon production (subsect. Viola). Hybrids with V. elatior and hairy morphs of V. rupestris inherit a dense, short indumentum. The habit of V. uliginosa and V. mirabilis is also easily recognized in their hybrids.
However, it is really difficult to discriminate between V. reichenbachiana and V. riviniana as parents in hybrids, and between V. canina, V. pumila and V. stagnina. The occurrence of the potential parents in the study area then becomes important; if several closely related species are present, biometric studies of fresh material and/or determination of chromosome number may be necessary, and it will in many cases be impossible to determine herbarium material.

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1 Stipules laciniate, often with a leaf-like apical segment (rarely coarsely dentate, but then spur at least 7 mm and lower petal violet with a yellow base)
2
- Stipules entire, fimbriate or coarsely dentate (if coarsely dentate, then spur not longer than 5 mm and lower petal never with a yellow base)
5
 
2 Spur at least 7 mm; stipules oblong-ovate, its apical segment not distinctly narrowed towards the base
- Spur shorter than 7 mm; apical segment of stipules leaf-like, narrowed towards the base
3
 
3 Petals as long as or shorter than the sepals; corolla cup-shaped, up to 1.5 cm diam., usually uniformly yellowish white
- Petals longer than the sepals; corolla flat, more than 1.5 cm diam., usually lilac or with different combinations of white, yellow, lilac and black
4
 
4 Corolla (1.5–)2–3(–3.5) cm diam.; petals hardly overlapping
- Corolla more than 3.5 cm diam.; petals strongly overlapping
 
5 Petals yellow; lateral petals directed obliquely upwards; leaf-blades wider than long, with scattered hairs on the upper surface, its apical tooth usually shorter than the lateral ones (Fig. )
- Petals lilac to white; lateral petals directed obliquely downwards; leaf-blades usually at least as long as wide (if wider than long, then leaf-blade glabrous on the upper surface and apical tooth overtopping the lateral ones)
6
 
6 With erect to ascending aerial stems; flowers from the aerial stems
7
- Aerial stems absent; flowers from the terminal rosette (sometimes also from creeping stolons)
14
 
7 Terminal leaf rosette present; middle stem leaves as long as wide or slightly longer than wide; stipules of middle stem leaves usually scarious (if green and leaf-like then at most 10 mm); spur white or lilac
8
- Terminal leaf rosette absent; middle stem leaves always much longer than wide; stipules of middle stem leaves mostly green and leaf-like, (5–)7–30 mm or more; spur white, yellowish or greenish
11
 
8 Petioles with an abaxial line of hairs; chasmogamous flowers from the leaf rosette; flowers from the aerial stems usually cleistogamous
- Petioles glabrous or hairy all over; all flowers from the aerial stems
9
 
9 Stipules ovate to lanceolate, denticulate; stems often densely puberulent
- Stipules narrowly lanceolate, fimbriate; stems glabrous or sparsely hairy at the nodes, rarely densely puberulent
10
 
10 Sepal appendages 0.4–0.8 mm; petals lilac, narrow, normally not overlapping; spur slender, pointed, lilac; stipules narrowly lanceolate, with 7–11 fimbriae which are often longer than the width of the stipule
- Sepal appendages 0.8–2.5 mm; petals blue, broad, normally overlapping; spur thick, blunt, white or lilac; stipules broadly lanceolate, with 5–8 fimbriae which are often shorter than the width of the stipule
 
11 Stems fairly densely hairy from short, slightly downwards-pointing hairs; tall, robust, erect plant
- Stems glabrous or very sparsely hairy; often low, slender, creeping to ascending plants
12
 
12 Leaf-blades of middle stem leaves 1.3–2 times as long as wide, often with shallowly cordate base; spur distinctly longer than the sepal appendages, whitish
- Leaf-blades of middle stem leaves 2–3 times as long as wide, with truncate or cuneate base; spur short, greenish
13
 
13 Leaf-blades with cuneate base; most stipules distinctly longer than the petiole
- Leaf-blades with truncate (or very shallowly cordate) base; most stipules shorter than the petiole
 
14 Petioles glabrous or almost so; flowers not scented
15
- Petioles distinctly hairy at least on the abaxial side; flowers scented (except in V. hirta)
18
 
15 Stipules almost subulate; leaves with at least some hairs above; sepals acute; spur 3–7 mm
16
- Stipules ovate to lanceolate; leaves glabrous above; sepals obtuse; spur 1–3 mm
17
 
16 Rhizome long, creeping; stipules entire; leaf-blades distinctly longer than wide
- Rhizome short, erect; stipules fimbriate; leaf-blades not longer than wide
 
17 Petals lilac to dark lilac (rarely white), large (spurred petal, including the spur, 14–20 mm); bracteoles in the upper half of the pedicel; leaves usually hairy beneath
- Petals pale greyish lilac, small (spurred petal, including the spur, 9–13 mm); bracteoles in the middle third of the pedicel; leaves often glabrous beneath
 
18 Petioles hairy only on the abaxial side; sepals acute; capsules trigonous, glabrous
- Petioles hairy all round; sepals obtuse; capsules globose, hairy
19
 
19 Without stolons; internodes up to 10 mm
20
- With rooting stolons longer than 10 mm
21
20 Stipules with at least 1 mm long fimbriae; petioles purple-tinged in the lower half; upper petals 4–6 mm wide; spur whitish
- Stipules with less than 1 mm long fimbriae; petioles not purple-tinged above the lower fifth; upper petals 6–9 mm wide; spur purple
 
21 Hispid from long hairs; stipules linear, long-fimbriate; flowers white; capsules greenish
18. V. alba
- Hairy from short hairs; stipules lanceolate to ovate; flowers violet (rarely white); capsules purplish
22
 
22 Stipules ovate, with up to 1 mm long fimbriae; leaf margin with 20–27 teeth; bracteoles c. 5 mm, in the middle third of the pedicel; flowers dark violet (rarely white)
- Stipules lanceolate, with 1–3 mm long fimbriae; leaf margin with 29–36 teeth; bracteoles 9–12 mm, in the lower third of the pedicel; flowers pale violet

1. Viola biflora L.       Map      ill.      (TM)

Linnaeus, Sp. pl.: 936 (1753). – Type: Linnaean Herbarium 1052.16 (LINN) lectotype, sel. by Qaiser & Omer, Fl. Pakistan 166: 20 (1984).

D Fjeld-Viol. F lapinorvokki. Fa . I fellafjóla. N fjellfiol. S fjällviol.

Hemicryptophyte. Rhizomatous, caulescent perennial. Rhizome ± creeping, 0.5–2 × 0.3–0.5 cm, unbranched, densely knotted from old leaf-bases, with terminal leaf rosettes. Rosette leaves 2–3(–4); stipules broadly lanceolate, 4–6 × 1–2 mm, ± acute, entire, glabrous; petiole 3–15 cm, slender; blade rather thin, broadly reniform to orbicular, 1.5–3.5 × 2–5 cm, wider than long; margin convex, crenate with 12–16(–20) teeth; base cordate; apex obtuse, apical tooth often shorter than the lateral ones; blade with scattered short hairs on the upper surface. Aerial stems 1–3(–many), 3–20 cm, slender and weak, mostly ascending, glabrous, sometimes with very short axial shoots bearing cleistogamous flowers. Stem leaves 2–4, upwards gradually smaller, more acute and with shorter petioles; stipules 4–5 × 2 mm, entire, acute, ciliate, green; petiole 0.3–10 cm; blade reniform, 1–3 × 1.5–4 cm, as long as wide or wider, with scattered hairs; margin crenate with 7–14 teeth; apex obtuse or (in upper leaves) shortly acuminate.
Chasmogamous flowers 1–2(–4), scentless, from the aerial stems. Pedicels of chasmogamous flowers glabrous, 1–6 cm; bracteoles 1–2 mm, near the middle of the pedicel. Sepals narrowly lanceolate, obtuse, 3–5 × 1–1.2 mm, with indistinct appendages. Petals yellow (very rarely yellowish white) with brownish violet venation towards the throat; upper petals obovate, 6–10 × 3–6 mm; lateral petals directed horizontally outwards, obovate, without hyaline hairs at the throat; spurred petal obovate to rhomboid, 7–13 × 4–8 mm including the spur; spur yellow, obtuse, c. 1 mm. Ovary glabrous. Cleistogamous flowers on short pedicels in axils of aerial stems, c. 1.5 mm. Capsule oblong-ovoid, c. 6 × 4 mm, glabrous, explosive. Seeds ellipsoid, pale to dark sepia; elaiosome small. – Late spring (chasmogamous flowers) and summer (cleistogamous flowers).
2n=12 (F EnL, N NNo, ØFi). - [2n = 12]
Distribution. MBor–MAlp. Alt. N MR 1500 m. – N common in the Scandes (from Ak Eidsvoll, Op Lunner, Te Seljord, AA Bykle and Ro Suldal); north and west of the Scandes also in the lowlands. S common in the Scandes from Dlr northwards; scattered to rare in eastern Lapland and the western parts of the coastal provinces south to Hls Färila and Ytterhogdal (formerly also Forsa, Järvsö and Los). F common in EnL and InL, scattered in northern KiL and SoL, apparently extinct in PeP Pello.
Outside Norden in N Siberia and in the mountains of S Europe and C and E Asia, in Japan, Alaska and Colorado. In Norden represented by subsp. biflora. Arctic and boreal populations are reported to differ much from more southern populations, e.g. those of C Asia.
Habitat. Open to half-shaded, somewhat moist places on eutrophic and humus-rich, often lime-rich soil. – Lush Alnus, Betula and Picea forest in and near the mountains, Salix thickets, pasture, early snowbeds, south-facing talus slopes and shelves, river banks and creeks.
Variation. The chasmogamous flowers vary much in size and in the relative size and shape of the petals. This variation occurs also within individuals and is without taxonomic importance; part of it is probably attributed to intermediacy between chasmogamous and cleistogamous flowers. – A variant with yellowish white flowers is known from N ST Oppdal and S Hrj Ljusnedal (Danielsson 1994, with photo).
Similar taxa. Viola biflora can, in the vegetative state, be confused with V. palustris (8), but the leaves of the latter are glabrous above and it has creeping stolons.

2. Viola tricolor L.

Linnaeus, Sp. pl.: 935 (1753). – Type: Linnaean Herbarium 1052.21 (LINN), lectotype, sel. by Banerjee & Pramanik in Panigrahi, Fasc. Fl. India 12: 36 (1982).

D Almindelig Stedmoderblomst. F keto-orvokki. Fa trílitt-blákolla. I þrenningarfjóla. N stemorsblom. S styvmorsviol.

Literature. Clausen 1922, 1931, Nauenburg 1986, Rasmussen 1954, Wittrock 1897.

Therophyte or hemicryptophyte. Annual, biennial or weakly perennial with a vertical taproot. Stems erect or ascending, to 40 cm, unbranched or usually ± richly branched especially in the lower parts, glabrous or ± hairy from short, recurved hairs. Leaves ciliate and sometimes also hairy on the veins beneath; sometimes glabrous. Stipules pinnatisect or almost palmatisect; terminal lobe larger than the lateral ones, lingulate to narrowly ovate. Petioles to 20 mm. Leaf-blades crenate; those of the lowermost leaves (soon withering) notably smaller than the middle ones, broadly ovate to lanceolate with cordate to cuneate base and obtuse apex, 3–13 × 4–10 mm, 1–2 times as long as wide; those of the middle and upper leaves ovate to lanceolate (gradually narrower in upper leaves) with truncate to cuneate base and acute apex, 9–35 × 3–7 mm, 1.5–5 times as long as wide.
Flowers with a honey-like scent, from the aerial stems. Pedicels to 15 cm. Sepals lanceolate to linear-lanceolate, acute, 5–10 × 1–2 mm (excluding the appendage); appendage semiorbicular or truncate, 1–2 × 0.9–2 mm, 0.1–0.3 times as long as the rest of the sepal. Corolla 1.5–3 cm high in front view, flat. Petals longer than the sepals, violet to white or rarely yellow, with dark violet streaks, spurred petal with a large yellow patch at the base; upper petals usually darker in colour, erect or recurved, obovate, 7.5–14 × 4–10 mm, 1.5–2.2 times as long as wide; lateral petals directed obliquely upwards, narrowly obovate, 6–13 × 3–8 mm, 1.5–2 times as long as wide, with hyaline hairs at the throat; spurred petal obdeltate, almost flat, 8–14 × 4–11 mm, 1.1–2 times as long as wide, its pollen groove closed by hairs distally; spur violet (rarely white), straight or ± curved, 2–5 × 0.9–1.5 mm, 1–2 times as long as the sepal appendages. Pollen grains with 4 pores (10–20% with 3 or 5). Style geniculate near the base, with a distinct apical flap. Capsule ovoid, trigonous, acute to obtuse, 4–7.5 × 2–3 mm, glabrous, explosive. Seeds ovoid, obtuse, pale to light brown, 1.5–2.5 × 0.8–1.5 mm; elaiosome small. – Spring to autumn.
2n=26 (D ØJy, F U, V, N Ak 2, S Sk 2). – [2n=26]
Distribution. For Norden, see the subspecies.
Most of Europe, east to the Urals and the Caucasus; SW Asia; mountains of NW Africa; naturalized in Asia, North America and Australia (subsp. tricolor). In the Alps also represented by subsp. subalpina Gaudin, in SE Europe two further subspecies.
Variation. Petal size and colour vary very conspicuously with development and with season. At the beginning of anthesis the petals are small, relatively wide, and frequently white; they increase to almost double size, elongate and become more intensely coloured for up to two days before the flower is fully developed. Flowers produced late in summer frequently have smaller, narrower and less intensely coloured flowers than those from the same plant in early summer.
The hereditary variation in flower colour is considerable. The most common condition is perhaps upper petals violet, lateral petals white, and spurred petal white with a yellow basal patch. Variants with lateral petals violet at the apex, or with all petals violet (upper ones often darker), are also common. Variants where mature flowers are entirely white or pale yellow are rarer. Also the relative width of the petals varies. Wittrock (1897) studied flower variation in detail and described numerous taxa to cover it; however, he only named a fraction of all variants existing, and there is no obvious geographical or ecological pattern in the variation. Clausen (1921, 1922, 1926) investigated the variation in selected characters both under natural conditions and with crossing experiments and concluded that the characters were not taxonomically significant.
The variation in habit is more important. Plants from sandy fields at or near the coast in the southern parts of Norden are usually perennating and are capable to produce new growth from stems that become covered with sand. They thus become strongly branched from the base and have partly procumbent stems. These features keep constant in cultivation (Wittrock 1897). These sand ecotypes usually also deviate in having narrower leaves and stipules, narrower upper petals and longer spurs. Similar variants are present at the southern coasts of the Baltic and along the Atlantic coast; they are all now usually referred to a separate subspecies (which is possibly polyphyletic), subsp. curtisii.
Material of Viola tricolor from A, V, U, EK, St and EP was referred by Hämet-Ahti et al. (2005) to V. tricolor var. maritima Hagen, here regarded as a synonym of V. tricolor subsp. curtisii. However, the Finnish plants deviate distinctly from the plants accepted as subsp. curtisii. The Finnish plants are usually erect, with coarse stems, have often dark blue flowers and are almost always annual, whereas subsp. curtisii, as interpreted here, is a slender plant with ascending, thin stems, often lightly coloured flowers and almost always biennial or weakly perennial. It grows in dune areas, whereas the Finnish plants often grow in scrub or on rock ledges.
Dwarfish plants from limestone pavement of S Öl were referred to V. tricolor by Lundqvist (1979); by Sterner (1938) they were, in part at least, referred to V. arvensis. Their taxonomic status has not been clarified.
Hybridization. Viola tricolor is one of the parents of Viola ×wittrockiana (5), and they hybridize freely. Hybrids are also known with V. arvensis.
Similar taxa. Viola tricolor is sometimes difficult to delimit from V. arvensis (3), and especially from hybrids with this species. In critical cases the average number of pores on the pollen grains should be investigated. ”Classical” variants of V. ×wittrockiana are easily distinguished from V. tricolor on much larger flowers which are frequently orbicular in outline. Nowadays sorts with small flowers and narrower, not or slightly overlapping petals are also popular. They are probably close to pure V. tricolor and the limit can only be drawn arbitrarily. – See also V. lutea and V. ×williamsii (rare casuals).

2A. subsp. tricolor      Map

Viola tricolor subsp. faeroënsis W. Becker (1908).

D Almindelig Stedmoderblomst. F kallioketo-orvokki. I þrenningarfjóla. N vanlig stemorsblom. S vanlig styvmorsviol.

Therophyte. Summer-annual, winter-annual or biennial (rarely short-lived perennial), hairy or sometimes almost glabrous. Stems erect, unbranched or branching above the soil surface, to 40 cm, green or sometimes tinged with violet. Leaves not fleshy. Stipules of middle and upper leaves 10–22(–35) mm, as long as or shorter than the petiole; lateral lobes (on the outer edge) 4–6(–7), narrowly lanceolate; terminal lobe lanceolate to narrowly ovate, sometimes leaf-like. Blade of lower leaves ovate with cordate base and fairly obtuse apex, 3–13 × 4–10 mm, 1–1.5 times as long as wide; blades of middle and upper ones elliptic to lanceolate with truncate to broadly cuneate base and broadly acute apex, 17–35 × 6–11 mm, 2–4.5 times as long as wide.
Sepals 7–10 × 1–2 mm (excluding the appendage); appendages 1–2 × 1–2 mm, 0.1–0.25 times as long as the sepals. Corolla violet to white or rarely yellow, with dark lilac veins; upper petals usually darker in colour, erect, 10–14 × 5–9 mm, 1.2–1.9 times as long as wide, lateral petals 11–13 × 6–8 mm, 1–1.9 times as long as wide; spurred petal 12–14 × 9–11 mm, 1.1–1.3 times as long as wide; spur violet, ± curved, 2–4 × 1.3–1.6 mm, 1–2 times as long as the sepal appendages. Capsule rounded in cross-section, obtuse, *** × *** mm. Seeds c. 1.5 × 1 mm.
Distribution. Nem–MBor(–NBor). Alt. N He 1080 m. – Partly native, partly anthropochorous (towards the north probably entirely so). D probably archaeophytic; common throughout, especially on sandy soils. N common except in VFi and ØFi. S probably indigenous north to Jmt and southern coastal Vb but mainly apophytic; on the mainland common north to ÅsL and Nb, in more northerly parts of Lapland scattered and ± ephemeral; fairly rare in Öl, from Gtl only known as a rare casual introduction and as an escape. F indigenous and common or fairly common on rock outcrops and rocky or stony shores north to EP, southernmost PH, central PS and PK; in the east common and abundant as a field weed; in the north a recent incomer, partly a wartime introduction. Fa probably anthropochorous; southern Streymoy and southern Sandoy. I IVe and INo fairly common and probably archaeophytic; a more recent introduction in the other coastal provinces (scattered in INv and IAu, rare in ISu) and a casual alien in IMi.
Most of Europe, east to the Urals and the Caucasus; Turkey; mountains of NW Africa; naturalized in Asia, North America and Australia.
Habitat. Sunny, dry to fairly dry sites with sparse vegetation; mainly on base-poor (but not necessarily nutrient-poor) mineral soils. – Probably indigenous (at least in part) on esker slopes, sandy fields, rock fissures, cliffs and bird-skerries; apophytic in shallow soil on flat bedrock in pastures, on roadsides and railway embankments and (especially formerly) on peaty roofs and as a weed of cultivated land. – Also cultivated and sometimes escaped.
Variation. Extremely variable, especially in flower size, shape and coloration (see under the species). The shape of the leaf-blades also varies, perhaps most notably within individuals: the lowermost leaves are fairly long-petiolate, have small stipules and an ovate blade with more or less cordate base and obtuse apex; towards the top the petioles gradually become shorter, the stipules larger and more divided, and the leaf-blades narrower with a cuneate base and acute apex. There is also a variation among populations, the most narrow-leaved variants having the same leaf-blade shape as some variants of subsp. curtisii.
Specimens from Fa have very broadly ovate leaf-blades, abruptly narrowed into the petiole and with very obtuse apex; the stipules are less deeply incised than in ordinary V. tricolor and the plants tend to become perennial. They were referred to a separate subspecies, subsp. faeroënsis, by Becker (in Ostenfeld 1908) but are here regarded as one extreme in the variation of subsp. tricolor. Icelandic plants tend to be biennial, with supraterrestrial branching and many ascending lateral stems.
A number of improved variants are grown for ornament.

2B. subsp. curtisii (E. Forst.) Syme      Map

Syme in Sowerby, Engl. bot. ed. 3, 2: 26 (1865). - Described from ***
V. tricolor subsp. ammotropha Wittr. (1897).
V. tricolor subsp. coniophila Wittr. (1897).
V. tricolor var. maritima Schweigg. ex K.G. Hagen (1819). – V. tricolor subsp. maritima (K.G. Hagen) Hyl. (1945).
V. tricolor subsp. stenochila Wittr. (1897).

D Klit-Stedmoderblomst. F dyyniketo-orvokki. Fa . I . N sandstemorsblom. S klittviol.

Hemicryptophyte. Short-lived perennial; fairly sparsely hairy or sometimes glabrous. Stems usually richly branched below the soil surface; subterranean parts whitish, covered with scale-like, fleshy leaves; aerial stems often purplish at base, to 30 cm; central stems erect, peripheral ones ascending to procumbent. Leaves slightly fleshy. Stipules of middle and upper leaves 9–18(–21) mm, shorter than the petiole; lateral lobes (on the outer edge) 3–5(–6), almost lingulate; terminal lobe ensiform, falcate or spathulate.. Blade of lower leaves ovate to lanceolate with broadly cuneate base and obtuse apex, 5–10 × 3–7 mm, 1.25–2 times as long as wide; blade of middle and upper ones ovate to narrowly elliptic with cuneate base and fairly acute apex, 9–16 × 3–7 mm, 1.5–5 times as long as wide.
Sepals 5–7 × 1–2 mm (excluding the appendage); appendages 1–1.8 × 0.9–1.7 mm, 0.2–0.3 times as long as the sepals. Corolla violet, rose, yellowish white, bright yellow or occasionally white, with dark lilac veins; upper petals recurved, 7.5–13.5 × 4–8.5 mm, 1.5–2.2 times as long as wide, lateral petals 6–11 × 3–7 mm, 1.5–2 times as long as wide, spurred petal 8–14 × 4–10 mm, 1.2–2 times as long as wide; spur violet or occasionally white, straight, 3–5 × 0.9–1.5 mm, 1.6–3 times as long as the sepal appendages. Capsule triangular in cross-section, acute, 4–7.5 × 2–3 mm. Seeds 1.5–2.5 × 0.8–1.5 mm.
Distribution. Nem–BNem. – D common on the west coast of Jylland from Skagen to Rømø and on Læsø and Anholt, scattered elsewhere except in Brn (rare, south coast only) and mainland ØJy (no records). N rare on the south coast but likely overlooked; at least Øf Hvaler and Rygge, VA Søgne and Farsund, Ro at least Hå, Klepp and Sola. S much overlooked; along the coast from BhG to Bl (apparently fairly common at least in Sk and there also inland in Brösarp and Degeberga); Öl and Gtl (also inland); Upl Djurö (Sandhamn).
Coasts of Europe from France and the British Isles to southernmost N; in the Baltic to Russia (St. Petersburg and Kaliningrad).
Habitat. Shifting sand, mainly on seashores; more rarely grassland on sand.
Variation. There is considerable variation between different stands; apparently the subspecies has a strong tendency to develop local races. Wittrock (1897) described three sand ecotypes from S as subspecies, viz. subsp. ammotropha (Sk Ystad; with fairly erect growth and rose flowers), subsp. coniophila (Gtl Fårö; petals dark lilac, upper ones strongly divergent, spurred one conspicuously wide), and subsp. stenochila (Gtl Sanda; fairly strongly hairy, with dark lilac petals, upper ones only slightly divergent, spurred one fairly narrow). These variants have been collected repeatedly at classical localities and appear to be genetically different. However, it was obvious already to Wittrock (1897) that several more variants are present.
In the British type locality subsp. curtisii has yellow flowers and for this reason the Nordic variants have sometimes been referred to a separate subspecies, subsp. maritima. Possibly the Nordic sand ecotypes are more closely related to subsp. tricolor than to subsp. curtisii in its narrowest sense (Nauenburg 1986); clearly the variation pattern needs to be studied more closely.

3. Viola arvensis Murray      Map

Murray, Prodr. stirp. Gott.: 73 (1770). – V. tricolor var. arvensis (Murray) Wahlenb. (1824). – V. tricolor subsp. arvensis (Murray) Gaudin (1828). – Type: Bauhin Herbarium, ”Viola Martia fol(iis) obl(ongis) 6, p. 200” (BAS) lectotype, sel. by Nauenburg, Willdenowia 21: 54 (1991).

D Ager-Stedmoderblomst. F pelto-orvokki. Fa . I arfafjóla. N åkerstemorsblom. S åkerviol.

Literature. Clausen 1922, 1931, Nauenburg 1986, Rasmussen 1954, Wittrock 1897.

Therophyte. Summer- or winter-annual with a slender, vertical taproot. Stems erect, to 40 cm, ± branching at base, glabrous or ± hairy from short, recurved hairs. Stipules pinnatisect; terminal lobe in lower leaves leaf-like, to 10 mm, shorter than the petiole, in upper leaves lanceolate, to 15 mm, longer than the petiole. Petioles with scattered hairs, 40 mm in lower leaves, to 10 mm in upper leaves. Leaf-blades pure green, crenulate to serrate with 5–6 teeth and cuneate base; those of lower leaves elliptic to ovate, broadly to narrowly cuneate, 15–20 × 10–13 mm, crenulate, obtuse; those of upper leaves narrowly elliptic, narrowly cuneate, to 30 × 10 mm, 2–3 times as long as wide, serrate and acute.
Flowers with a honey-like scent, from the aerial stems. Pedicels to 10 cm. Sepals lanceolate, 6–8 × 1.6–2.2 mm (excluding the appendage); appendage truncate, 2–2.5 × 1.6–2.2 mm, 0.3–0.35 times as long as the sepals. Corolla to 15 × 10 mm in front view. Petals shorter than or as long as the sepals, rarely longer, white to very pale yellow or sometimes partly violet, often with dark streaks, spurred petal with a yellow patch at the base; upper petals recurved, obovate, 7–8 × 4–5 mm; lateral petals recurved, obovate, 7–8 × 4–5 mm, with hyaline hairs at the throat; spurred petal obdeltate, concave, 10 × 8 mm, its pollen groove open distally; spur violet, conical or cylindric, blunt, straight, 5 mm, 2 times as long as the sepal appendages. Pollen grains with 5 pores (5–10% with 3 or 4). Style geniculate near the base; apical flap indistinct or absent. Capsule ovoid, trigonous, obtuse, 6–8 mm, glabrous, explosive. Seeds ovoid, light brown to brown, 1.5–2 × 0.8–1 mm; elaiosome small. – Early spring to late autumn.
2n=34 (D FyL, F V, N Ak, S Sk). – [2n=34]
Distribution. Nem–MBor(–NBor). Alt. N ST 700 m. – Archaeophytic in the south. common, especially in eastern Jylland and the islands. N common in the lowlands north to NT; casual further north to Tr Tromsø and Storfjord (partly a wartime incomer). S common north to Dlr and along the coast and the major river valleys north to Nb; in the northern inland more scattered and, especially near the mountains, casual. common north to PeP and Ks, further north rare and casual. I IVe Reykjavík 1939 and 1940 (garden and nursery), INv 1956 and IAu 1963 (farm).
Most of Europe and W Asia, probably indigenous in SE Europe and SE Asia; naturalized in Australasia and N America (also Greenland).
Habitat. Dry to moderately damp open sites on more or less nutrient-rich clay, till or sand. – Arable land, gardens, roadsides, pastures, railways, waste ground and exposed soil; sometimes in dry slopes and in shallow soil on rocks.
Biology. Largely autogamous. The pollen groove on the spurred petal is open and the head of the style is closely approached to the pollen already at the beginning of anthesis. The flowers are, however, visited by insects and very likely some cross-pollination occurs.
Variation. Variable in flower size and relative size of petals in relation to sepals. Late flowers are often smaller than summer flowers and sometimes have very small, almost rudimentary petals. The flowers are usually white or whitish yellow, but the upper petals are sometimes violet at the apex; rarely the violet colour is more extended.
Hybridization. Hybrids of Viola arvensis are known with V. cornuta, V. tricolor (both subspecies) and V. ×wittrockiana.
Similar taxa. Viola arvensis is sometimes hard to distinguish from variants of V. tricolor, and even more so from hybrids between these two taxa. In critical cases the average number of pores on the pollen grains should be investigated.

4. Viola cornuta L.   Map

Linnaeus, Sp. pl. ed. 2: 1325 (1763). – Described from the Pyrenees.

D Horn-Stedmoderblomst. F sarviorvokki. Fa . I hornfjóla. N hornfiol. S hornviol.

Hemicryptophyte. Rhizomatous, caulescent, arosulate perennial. Stems erect to ascending, to 40 cm, glabrous or with a line of hairs. Stipules conspicuous, broadly and obliquely ovate, deeply serrate, sometimes with entire, triangular apex, 13–15(–20) × 7–13(–16) mm, green, ciliate and hairy on the veins beneath, glabrous above, usually longer than the petiole. Petioles 7–13 mm. Leaf-blades ovate, oblong-ovate or elliptic, 19–30 × 10–19 mm, hairy like the stipules; margin serrate with obtuse teeth; base rounded to slightly cordate; apex obtuse.
Flowers with a honey-like scent, from the upper part of the stems. Pedicel 9–15 cm, much longer than the subtending leaf. Sepals very narrowly lanceolate, acute, 10–13 mm (excluding the appendage); appendage truncate, 1.5–3 mm, 0.1–0.2 times as long as the rest of the sepal. Corolla 3–4 ´ 2–3 cm in front view, flat. Petals a deep violet, spurred petal with a small yellow patch at the base, not overlapping; upper petals 15–20 × 7–11 mm, 1.8–2.1 times as long as wide; lateral petals directed slightly downwards, 14–15 × 7–9 mm, 1.6–2 times as long as wide, with hyaline hairs at the throat; spurred petal 15–16 × 11–14 mm, 1.1–1.5 times as long as wide; spur violet, slightly curved, 10–15 mm, 6–9 times as long as the sepal appendages. Style geniculate near the base, with a distinct apical flap. Capsule ovoid. – Summer.
[2n = 22]
Distribution and habitat. Grown for ornament, although in most areas more rarely than its hybrids (see the rare casual V. ×williamsii), and occasionally escaped.. N Ak Oslo 1961, Ro Karmøy 1898, SF Høyanger and Hyllestad 1994 and MR Sykkylven 1995. S Sk Hörby 1915 (railway bank), Klm Ljungby 1956 (railway bank), Oskarshamn 1913–19, BhG Mölndal (filling soil) 1934. – Records from N Bu and Ho (Lid & Lid 2005) refer to V. ×williamsii; those from Øf, Ak Bærum, VA and ST have not been checked; no correctly determined V. cornuta has been seen from D; there are c. 60 records from S, and a few from F, which could not be evaluated due to lack of vouchers.
The Pyrenees.
Hybridization. Hybrids of Viola cornuta are known with V. arvensis and V. ×wittrockiana (V. ×williamsii, rare casual).
Similar taxa. Viola cornuta is similar to V. ×wittrockiana (5) but differs by uniformly violet, narrow petals which do not cover each other, much longer spur and ovate, deeply serrate but not laciniate stipules without a leaf-like apical lobe. Their hybrid is still more similar (diagnostic characters see V. ×williamsii, rare casual).

5. Viola ×wittrockiana Gams ex Kappert   Map

Kappert, Mollers Deutsch. Gartner-Zeitung 47: 294 (1932).
Viola altaica × tricolor × lutea

D Have-Stedmoderblomst. F tarhaorvokki. Fa . I . N hagestemorsblom. S pensé.

Therophyte. Rhizomatous, caulescent, erect annual. Stems erect, angled, to 30 cm, glabrous or with a line of hairs. Stipules conspicuous, obovate, deeply pinnatifid to palmate with strongly enlarged apical lobe, green, ciliate and sometimes hairy on the veins beneath, glabrous above, lower ones shorter than the petiole, upper ones longer than the petiole; apical lobe leaf-like, oblanceolate to obovate, obtuse; lateral lobes pointing outwards. Petioles 10–30(–50) mm. Leaf-blades ovate to lanceolate, 30–50 × 19–31 mm, hairy like the stipules; margin crenate to serrate with obtuse teeth; base cuneate to slightly cordate; apex obtuse.
Flowers scentless, from the middle and upper part of the stems. Pedicels 4–10(–18) cm, longer than the subtending leaf. Sepals lanceolate, abruptly narrowed into an acute apex, 8–12 mm (excluding the appendage); appendage truncate, 2–5 mm, 0.2–0.4 times longer than the rest of the sepal. Corolla 2–6.5 × 1.5–6 cm in front view, flat. Petals very variable in colour and colour pattern, with strongly overlapping margins; upper petals 10–37 × 8–44 mm, 0.8–1.2 times as long as wide; lateral petals directed outwards or upwards, 7–29 × 6–35 mm, 0.8–1.3 times as long as wide, with hyaline hairs at the throat; spurred petal 7–25 × 9–35 mm, 0.5–1 times as long as wide; spur usually violet, straight, 2–7 mm, 1–1.7 times as long as the sepal appendages. Style straight, papillose at the tip. Capsule ovoid. – Spring to autumn.
Distribution and habitat. Very often grown for ornament; a frequent escape on tips, filling soil, throwout and ruderal ground. D probably scattered throughout. N scattered records north to VFi Hasvik and ØFi Sør-Varanger. S recorded from most provinces north to Vrm, Nrk and Upl and from Hls, Mpd and Nb, often from numerous localities; very likely under-recorded. F collected or reported north to PeP, especially from U and EH.
Originated in the 1810’s in the British Isles from hybrids between V. lutea, V. tricolor and V. altaica Ker-Gawler (Wittrock 1895); cultivated and escaped in temperate areas worldwide.
Variation. As a result of development and improvement especially the flowers are extremely variable in shape, size and colour.
Hybridization. Viola ×wittrockiana was bred from hybrids of V. altaica, V. lutea and V. tricolor. Hybrids are known with V. tricolor (2), V. arvensis (3) and V. cornuta (V. ×williamsii, rare casual).
Similar taxa. Viola ×wittrockiana may be hard to delimit from related (notho-)taxa. Diagnostic characters are given under V. cornuta (4) and V. ×williamsii (rare casual).

6. Viola selkirkii Pursh ex Goldie       Map      ill.

Goldie, Edinb. Phil. J. 6: 324 (1822). – Described from North America.
V. umbrosa (Wahlenb.) Fr. (1828).

D Dal-Viol. F kaiheorvokki. Fa . I . N dalfiol. S skuggviol.

Literature. Aronsson 1999.

Hemicryptophyte. Acaulescent, non-stoloniferous perennial. Rhizome usually short and erect, 1.5–4 mm thick, ± unbranched, densely articulate and with terminal leaf rosette, occasionally 0.5 mm thick, creeping; internodes to 10 mm. Leaves 2 to many; stipules adnate to the petiole in the lower third to half to form a sheath, lanceolate, 10–15 × 1.5–3 mm, pale, acute, remotely and shortly glandular-fimbriate; petiole 2–8 cm, usually glabrous; blade cordate, 2.5–5 × 2–4 cm, with scattered long hairs above; margin sinuate to crenate and slightly undulate, with (9–)12–15 teeth; base cordate; apex acuminate; outer protective leaves consisting only of the basal sheath (with much reduced petiole and blade), tricuspidate, 5–13 × c. 3 mm, often purplish.
Chasmogamous flowers scentless, from the leaf rosettes, often not produced. Pedicels of chasmogamous flowers ± sparsely pubescent, (2.5–)4–7(–10) cm, not or slightly surpassing the leaves at time of flowering; bracteoles 4–8 mm, at the middle of the pedicel. Sepals ovate-lanceolate to lanceolate, acute, 5–6 × 2 mm (including the appendage); appendage conspicuous, denticulate, c. 2 mm. Petals pale violet, obovate; upper petals 8–11 × 4–5 mm; lateral petals without hyaline hairs at the throat; spurred petal 12–18 × 5 mm including the spur; spur pale violet, thickened towards the rounded tip, 4–7 mm. Ovary glabrous. Cleistogamous flowers 2–4 mm. Capsule broadly ellipsoid, c. 7 × 3.5 mm, glabrous and with purple stains, at first nodding, erect at maturity, explosive. Seeds ellipsoid, c. 1 mm, cream-coloured; elaiosome small. – Early spring (chasmogamous flowers) and summer (cleistogamous flowers).
[2n = 24]
Distribution. (BNem–)SBor–MBor(–NBor). Continental. Alt. N Op 760 m. – N rare and declining: the eastern parts from Te Kviteseid and Ak Asker north to ST, west to MR Sunndal; isolated in NT Leksvik 1920, SNo Alstadhaug 1841 (specimen not checked) and NNo Saltdal 1937. S widespread especially in the large river valleys from central Vrm, Dlr and Hls to Jmt and Ång; rare north to TL and Nb. F fairly common in EH and in the east north to Kn, elsewhere rare north to southeastern EnL (Ounastunturi); absent from most of the coast (present in St) and the far northeast. – Also given for N SNo Brønnøy (Lid & Lid 2005), but the specimen is V. riviniana; the source is unknown for a report from S Gst (Hultén 1950).
Circumboreal (also SW Greenland); isolated localities in Sichuan (C China), Colorado and New Mexico.
Habitat. Shady moist places on moss and peaty soil, river gorges, ravines, cliffs and scree; basiphilous. – Deep old spruce forest, seasonally flooded Alnus incana forest; very rarely in meadows and in fairly dry woodland. Apparently negatively affected by modern forestry and other human activity and rapidly declining in densely populated areas (e.g. N Ak).
Biology. Chasmogamous flowers are often not produced under natural conditions but sometimes appear in profusion after thinning or clearing.
Similar taxa. The leaf dentation of Viola selkirkii is characteristic, with distinctly incurved teeth and a slightly undulate leaf margin. Young leaf rosettes of Viola riviniana are similar, but in that species the stipules are not adnate to the petiole. – V. selkirkii is also somewhat similar to V. collina in leaf shape, but that species has obtuse sepals and globose capsules borne on decumbent pedicels; it grows mainly in dry, open places.

7. Viola epipsila Ledeb.       Map      ill.

Ledebour, Ind. sem. Hort. Dorpat.: 5 (1820). – Described from Estonia (Tartu).
V. suecica Fr. (1849).
V. scanica Fr. (1845).

D Tørve-Viol. F korpiorvokki. Fa . I birkifjóla. N stor myrfiol. S mossviol.

Literature. Brandrud 1989, Brandrud & Borgen 1987, Clausen 1931, Rasmussen 1954.

Hemicryptophyte. Acaulescent, stoloniferous perennial. Rhizome creeping, with 3–10 mm long internodes, rooting, with lateral long-jointed stolons. Leaves 1–3 in a rosette, scattered or absent on stolons; stipules ovate-lanceolate, 5–10(–13) × 2–3 mm, white-scarious or outer ones purplish, acute, entire; petiole (3–)7–12 cm, in fruit up to 20 cm, narrowly winged, glabrous or sometimes slightly hairy in the upper part; blade broadly cordate, orbicular or reniform, (1–)2.5–5 × 1.5–5.5 cm, in fruit up to 10 × 10 cm, glabrous above, usually with ± scattered 0.2–0.8 mm long, hyaline hairs beneath; margin shallowly crenate with 14–21 teeth; base cordate to deeply cordate; apex subacuminate or obtuse, rarely rounded.
Chasmogamous flowers 1–2, with a honey-like scent, from the terminal rosettes. Pedicels of chasmogamous flowers stout, glabrous or sometimes hairy in the upper part, 5–15 cm; bracteoles 1– 4 mm, in the upper half of the pedicel. Sepals broadly lanceolate, obtuse, 5–7.5 × 1.5–2.5 mm (including the appendage); appendage short and rounded, c. 1 mm, sometimes with scattered hairs. Petals lilac to dark violet or occasionally white, concolorous, obovate; upper petals 10–13 × 4–6 mm; lateral petals directed downwards, without or with sparse hyaline hairs at the throat; spurred petal dark-veined, (13–)14–20 × 5–8 mm including the spur; spur thick and slightly curved upwards, obtuse, 1.5–3 mm. Ovary glabrous. Cleistogamous flowers c. 4 mm. Capsule oblong, 8–14 × 5–6 mm, glabrous, explosive. Seeds ellipsoid, c. 1 × 2 mm, dark sepia; elaiosome small. – Late spring to early summer (chasmogamous flowers) and summer (cleistogamous flowers).
2n=24 (D Sjæ, F Ks, N Ak 8, Op, Bu 3, Vf). - [2n = 24]
Distribution. Nem–NBor(–LAlp). Continental. Alt. N Op 1260 m. – Throughout most of Norden, but declining in the south mainly because of habitat deterioration. D rare and declining, now only NJy Rold Skov, ØJy c. 5 localities since 1975 and Sjæ Farum, Rådvad and Store Dyrehave; formerly more abundant in these provinces and also found in VJy latest Ribe and Sønder Farup 1983, FyL latest Dalum and Ebberup 1957, LFM Horreby Lyng 1876, Stubberup 1973. N fairly common from Øf and Te (at least Skien and Porsgrunn) northwards, but rare or absent W of the southern Scandes (with certainty known only from SF Bremanger and Lærdal and MR Sunndal). S common south to Dlr and Hls (slightly less so near the coast); scattered further south to central Vrm, Nrk, Ög and northernmost SmI, and in central Vg; Hl Halmstad 1895; formerly numerous localities in Sk but very few remaining. F very common in the north, rather common inland south to the southern parts of EH and ES, rare or scattered in the southern coastal areas. I fairly common in central and eastern INo and northern IAu, rare in IVe and lower parts of northern IMi. – Reports from N AA, VA, Ro, Ho, Klm, Dls, and F A could not be confirmed (existing specimens are either undeterminable or belong to V. palustris).
Incompletely circumboreal in at least two races: subsp. epipsila in NW Eurasia E to Altai, and subsp. repens (Turkz. ex Trautv. & Meyer) W. Becker in NE Eurasia east of the Jenitsey river and in NW North America.
Habitat. Open to half-shady, wet, undisturbed habitats, often in Plagiomnium moss; basiphilous (soil pH 5–7). – Margins of (and tussocks in) eutrophic fens, wet Salix thickets, forest swamps, wet alluvial meadows. Becomes edaphically more demanding at its southern limit of distribution (soil pH > 6).
Variation. Viola epipsila varies greatly with respect to pubescence, even within single individuals and populations. Glabrous morphs, as well as morphs with hairs on the sepal appendages and on the uppermost parts of the pedicels, occur throughout Norden. In plants from northern D (NJy and to some extent VJy and ØJy) the leaves are glabrous or hairy only on the veins and do not have a prominent apex. They may at least in part belong to the hybrid with V. palustris.
The Nordic plants fall into two morphological groups. Plants from the northern parts of Norden (N Tr, VFi, ØFi, S from Vb and ÅsL northwards, F from PK, Kn and OP northwards) are generally smaller in the vegetative parts and have cordate or sometimes nearly triangular leaves longer than wide and with an acute or acuminate apex. Southern plants (D, N north to NT, S north to Dlr and Gst, F north to EP, PH and ES) are usually large, especially in fruit, and have more or less orbicular leaves with an obtuse or only shortly acuminate apex. A zone of transition between the two races occurs in the intermediate areas in mid-latitude Norden (F PS, KP, N SNo, NNo and S Hls, Hrj, Mpd and Jmt). This pattern of variation is probably a consequence of independent postglacial recolonisation from north and south of the Baltic Sea, possibly from different refugial source populations. The northern race was originally referred to as V. suecica Fr., but this name was later applied to morphological “intermediates” between V. epipsila and V. palustris (Brandrud 1989).
Hybridization. Hybrids of Viola epipsila are known with V. palustris.
Similar taxa. It is often impossible to confirm the identity of alleged Viola epipsila herbarium specimens. Diagnostic characters are given under the similar V. palustris (8) and their hybrid V. epipsila × palustris.

8. Viola palustris L.       Map      ill.

Linnaeus, Sp. pl.: 934 (1753). – Type: Linnaeus, Lapland Herbarium 278 (LAPP) lectotype, sel. by Jonsell & Jarvis, Nordic J. Bot. 22: 82 (2002).

D Eng-Viol. F suo-orvokki. Fa ljós blákolla. I mýrfjóla. N myrfiol. S kärrviol.

Literature. Brandrud 1989, Brandrud & Borgen 1987, Clausen 1931, Rasmussen 1954.

Hemicryptophyte. Acaulescent, stoloniferous perennial. Rhizome creeping, with 3–10 mm long internodes, rooting, with lateral long-jointed stolons. Leaves 1–4 in a rosette, scattered on stolons; stipules ovate-lanceolate, 5–10 × 2–3 mm, white-scarious or outer ones purplish, acute, entire; petiole 2–9 cm, in fruit up to 15 cm, narrowly winged, glabrous or sometimes slightly hairy in the upper part; blade broadly ovate, orbicular or reniform, 0.8–5 × 1–5 mm, in fruit up to 8 × 8 cm, glabrous or with scattered short hairs beneath; margin shallowly crenate with 12–23 teeth; base cordate to deeply cordate; apex rounded or obtuse.
Chasmogamous flowers 1–3, with a honey-like scent, from the terminal rosettes. Pedicels of chasmogamous flowers stout, glabrous or sometimes with scattered hairs near the base, 2.5–12(–20) cm; bracteoles 2–3 mm, in the middle third of the pedicel. Sepals broadly lanceolate, obtuse, 3.5–5.5 × 1–2 mm (including the appendage); appendage short and obtuse, c. 1 mm. Petals pale greyish lilac, paler in the throat, obovate; upper petals 5–11 × 2.5–5 mm; lateral petals directed downwards, with or without sparse hyaline hairs at the throat; spurred petal dark-veined, 9–13 × 4–7 mm including the spur; spur thick, obtuse, c. 1 mm. Ovary glabrous. Cleistogamous flowers c. 4 mm. Capsule oblong, 8–11 × 5 mm, glabrous, explosive. Seeds ellipsoid, c. 1 × 1.5 mm, dark sepia; elaiosome small. – Late spring to early summer (chasmogamous flowers) and summer (cleistogamous flowers).
2n=48 (F EK, U, V 3, N Øf 2, Ak 4, Bu 2, Vf 2, Te 5), c. 48 (N Te), 46–48 (F EH 2). - [2n = 48]
Distribution. Nem–LAlp. Alt. N Op 1750 m. – D common in Jylland, western FyL, northern, eastern and central Sjæ, elsewhere scattered to rare. N mostly common, but fairly rare in VFi and ØFi. S mostly common, but absent from Gtl and fairly rare in Öl; in Lapland notably rare east of the Scandes (but common in the mountains as well as near the border to the coastal provinces). F mostly common, but scattered to rare in northern Lapland. Fa common (not recorded from Stóra and Lítla Dímun). I mostly common, rare only in the dry area north of Vatnajökull.
Discontinuously circumboreal in several poorly differentiated races (Sorsa 1968). Nordic plants belong to the Amphi-Atlantic subsp. palustris, distributed from NE France and Britain east to Ural, the Azores, Greenland and NE North America. Plants from SW Europe (Portugal, Spain, SW France and parts of Britain) have been delimited as subsp. juressii (Link ex Wein) Cout. (2n=48). E Eurasian and W North American plants may belong to other races.
Habitat. In a wide range of open to half-shady wet habitats, preferably in Sphagnum moss on acidic soils (pH 3.9–6.0). – Margins of (and tussocks in) mesotrophic to oligotrophic fens, oligotrophic Picea and Alnus incana swamps, wet pasture. Hemerophilous, colonizing e.g. ditches, wet clear-felled areas and abandoned arable fields on former peatland.
Variation. The species is very variable with respect to the presence of hairs, which may vary much even within a single individual. Short hyaline hairs on the veins of the lower leaf surface occur rather frequently on summer leaves. Plants from southern F are sometimes hairy also between the veins (as in V. epipsila). Hyaline hairs sometimes occur in the lower part of the pedicel. Phenotypic plasticity has been reported also in other characters, including the number of rosette leaves and the length of petioles and pedicels (Evans 1956).
Taxonomy. Viola palustris is an allopolyploid with a probable origin in hybrids between V. epipsila and another, unknown taxon.
Plants from southern F have been reported to possess aneuploid chromosome numbers, 2n=30–48 (Sorsa 1965). This was interpreted as resulting from introgression from V. epipsila (2n=24). Morphologically similar “hybrids”, invariably with 2n=48, have also been reported from Poland (Kuta 1989) and perhaps S Upl (Eklund 1934). However, most of these plants seem to fall within the morphological range of pure V. palustris (Brandrud 1989). V. palustris and V. epipsila appear to be separated by sterility barriers in N (Brandrud 1989) and Poland (Kuta 1989), and completely sterile hybrids have been seen at least from F EH Lammi. The results of Sorsa (1965) are therefore in need of confirmation. A critical revision of the entire subsect. Stolonosae in Norden and worldwide is needed.
Hybridization. Hybrids of Viola palustris are known with V. epipsila.
Similar taxa. Luxuriant specimens of Viola palustris often have somewhat acute leaves and hairs on the lower leaf surface; they can be difficult to distinguish from V. epipsila (7) and from V. epipsila × palustris in particular. V. palustris usually differs from V. epipsila in having more numerous leaves with distinctly shorter hairs beneath, bracteoles usually in the lower part of the pedicel (in chasmogamous flowers), and smaller flowers. Both species differ from the hybrid in being fully fertile. – See also V. biflora (1).

9. Viola rupestris F.W. Schmidt       Map      Ill.

Schmidt, Neue Abh. Böhm. Ges. 1: 60 (1791). – Described from the Czech Republic (Bohemia).

F hietaorvokki. Fa . I . N sandfiol.

Literature. Nordal & Jonsell 1998, Nordal et al. 2005.

Hemicryptophyte. Rhizomatous, caulescent perennial, glabrous or (usually) hairy from dense, 0.05–0.2 mm long, patent or slightly downwards-pointing hairs. Rhizome vertical or ascending, 2–4 mm thick, sometimes branching below the soil surface, covered with numerous withered stipules, with a terminal leaf rosette. Rosette leaves 3–6; stipules subulate, 4–7 mm, brown, hairy or glabrous, with 2–6 narrow fimbriae about equalling the width of the stipule; petiole to 5.5 cm, hairy or glabrous; blade broadly rounded triangular or reniform, (5–)9–23(–30) × (5.5–)7–22(–32) mm (summer leaves to 45 × 40 mm), 0.6–1.4 times as long as wide, pure to dark green; upper surface hairy or glabrous, lower surface with more sparse hairs or glabrous; margin finely crenate or entire; base cordate to deeply cordate or truncate; apex subacute to obtuse. Aerial stems developing before chasmogamous flowering, erect or ascending, to 9 cm (summer shoots to 20 cm, ascending), hairy or glabrous. Stem leaves (0–)1–4 (in elongated stems to 8); stipules narrowly lanceolate, 5–9.5 mm, green but turning dark with age, with forward-pointing tapering fringes about equalling the width of the stipule at the point of attachment; petiole to 15 mm (in summer shoots to 25 mm), decreasing in length towards the top of the stem, hairy or glabrous; blade of middle stem leaves triangular to broadly triangular with rounded margins, 6–18 × 7–17 mm, 0.8–1.4 times as long as wide, pure to dark green; hairiness as in the rosette leaves; margin minutely crenate or entire; base cordate to deeply cordate or truncate; apex subacute to obtuse.
Chasmogamous flowers scentless, from the middle or upper part of the aerial stems. Pedicels hairy or glabrous, to 5 cm, longer than the subtending leaves at time of  flowering; bracteoles linear-lanceolate, sometimes fimbriate, in the upper half of the pedicel. Sepals hairy or glabrous, lanceolate, acute, upper ones 2.7–5 × 1–1.8 mm, lateral ones 4.5–7.5 × 1.3–2.5 mm (in both cases excluding the appendage); appendage suborbicular to rectangular, on upper sepals 0.5–2 ×  0.9–2 mm, on lateral ones (0.8–)1–2 × (1.2–)1.8–2.6 mm, all 0.15–0.4 times as long as the rest of the sepal. Corolla 11.5–19 × 12–19 mm in front view, 0.9–1.2 times as high as wide. Petals violet to light violet blue, whitish at the base, overlapping; upper petals reflexed to erect, broadly ovate to elliptic, 6–9.5(–12) × 3–7 mm, 1.8–2.4 times as long as wide; lateral petals broadly elliptic to obovate to narrowly obovate, 8–12 × 3.7–6 mm, 0.9–2.4 times as long as wide, with hyaline hairs at the throat; spurred petal slightly concave, 7.2–12 × (4.5–)5.8–8 mm excluding the spur, 1.4–2 times as long as wide, with 6–9 distinct veins at the throat; spur light violet blue or greenish white, thick, straight, blunt, (4–)4.7–9.5 × (2–)2.2–3.3 mm, 1.5–2 times as long as wide, 3–7 times as long as the sepal appendages. Style not papillose. Cleistogamous flowers 3–4 mm, lower sepal appendages longer than the upper ones, 1.4–2.5 mm. Capsule ovoid, trigonous, obtuse, 6.2–8.5 mm, hairy or glabrous, explosive. Seeds ellipsoid, 1.5–2.2 × 0.8–1.9 mm, pale to light brown; elaiosome small.
[2n=20] - See also the subspecies.
Distribution. Nem–LAlp. [Continental?] – Widespread in the southern and eastern lowlands but absent or rare in D, southwest N and S and in the Bothnian area; also in the northern Scandes and northeastern F; see further below (Variation) and under the subspecies. – Reported from D NJy Thy, Sjæ Gribskov and Thureby by Clausen (1931), but the specimens belong to V. riviniana.
Northern Eurasia.
Variation. In Norden, Viola rupestris is represented by two form series, generally recognized as subspecies. One (subsp. relicta) is northern, restricted to the Scandes and its outliers and morphologically homogeneous, the other (subsp. rupestris) is widely distributed but nearly exclusively in the lowlands (absent from the far north and northwest); it is variable in particular in hairiness, flower size and colour, and leaf size.
Analyses of isozymes have shown that the subspecies differ constantly in three loci, and that subsp. relicta, in contrast to subsp. rupestris, shares a unique allele with a supposedly relictual population confined to a few limestone outcrops in northern England. For that reason a western immigration route to Norden was suggested for subsp. relicta (B. Jonsell et al. 2000). That view was supported when it turned out that the isolated, westernmost population of V. rupestris in MR coincides with subsp. relicta in morphology and isozymes (Nordal et al. 2005). Jalas (1950) distinguished subsp. relicta from subsp. rupestris on a number of characters, including various details in flower shape and size, as well as in colour and texture of the leaves. Nordal & Jonsell (1998) found constant differences only in leaf shape (leaf base more truncate in subsp. relicta) and hair type (short, almost papilla-like in subsp. relicta). With support of the unique isozyme genotype subspecies rank is, however, well warranted.
The most conspicuous variation of subsp. rupestris is that of hairiness, but no geographic pattern or correlation with other characters is seen. In most specimens, the peduncles, petioles, sepals and young capsules are fairly densely covered by very short hairs (0.1–0.2 mm long; longer hairs rather indicate hybridization). The leaves are usually hairy above and often glabrous beneath. Subglabrous or slightly hairy specimens occur, and there is a small proportion of completely glabrous individuals, recognized as var. glaberrima Murb. (Murbeck 1887). In Öl, local populations are hairy or glabrous; elsewhere, populations are ± uniformly hairy.
The shape and size of leaf-blades shows some regional variation; it has been confirmed in cultivation that it is genetically conditioned (Nordal & Jonsell 1998). Material from S Öl (whether hairy or glabrous) usually have small (to 10 × 10 mm) leaf-blades, short petioles and short internodes and may be interpreted as an alvar ecotype. Large leaves are characteristic of populations in Jmt and Ks. In the latter area, the leaf-blades are also fairly narrow and distinctly cordate. The isozyme genotype of the isolated population group in Ks deviates distinctly from all other Nordic material, suggesting immigration from the east. – The material from F Ks (and more tentatively also some from inner central N ST) has been attributed to subsp. relicta in some treatments (e.g. Nilsson 1986); however, neither morphology nor isozymes support that view.
Hybridization. Hybrids of Viola rupestris are known with V. canina, V. mirabilis, V. pumila, V. reichenbachiana and V. riviniana.
Similar taxa. Viola rupestris (especially glabrous forms) is sometimes confused with V. riviniana (11), but they differ in stipule shape; see also under the latter.

9A. subsp. rupestris       Map      Ill.

V. arenaria DC. (1805). – V. rupestris var. arenaria (DC.) G. Beck. (1892). – V. rupestris subsp. arenaria (DC.) Rothm. (1963).

D Sand-Viol. F hietaorvokki. N vanlig sandfiol. S sandviol.

Indumentum (if present) of 0.1–0.2 mm long, patent or slightly downwards-pointing hairs. Basal leaves with petiole up to 5.5 cm; blade (5–)9–23(–30) × (5.5–)7–22(–32) mm (summer leaves up to 45 × 40 mm), 0.6–1.4 times as long as wide; base cordate to deeply cordate or truncate; apex subacute or obtuse. Aerial stems to 9 cm (summer shoots to 20 cm, ascending). Stem leaves (0–)1–4 (in elongate stems up to 8); petiole to 15 (in summer shoots 25) mm; blade of middle stem leaves 6–18 × 7–17 mm, 0.8–1.4 times as long as wide; base cordate to deeply cordate or rarely truncate.
Pedicels to 5 cm. Upper sepals 2.7–5 × 1.1–1.8 mm, lateral ones 4.5–7.5 × 1.3–2.5 mm (in both cases excluding the appendage); upper appendages 0.6–2 × 0.9–2 mm, lateral ones (0.8–)1–2 × (1.2–)1.8–2.6 mm. Corolla 11.5–19 mm high × 12–19 mm wide in front view. Petals violet to light violet blue; upper ones broadly ovate to elliptic, 6.2–9.5(–12) × 4–7 mm; spurred petal 7.2–12 × (4.5–)5.8–8 mm excluding the spur; spur light violet blue or greenish white, (4–)4.7–9.5 × (2–)2.2–3.3 mm. Cleistogamous flowers sometimes on the summer stems. Capsule 6.7–8.5 mm. Seeds 1.5–2 × 0.8–1.2 mm. – Early spring to mid-spring.
2n=20 (N ST). – [2n=20]
Distribution. Nem–LAlp. Alt. N Op 1260 m. – scattered, although locally fairly common, in the southeast from Øf Hvaler and Te Porsgrunn north to He Engerdal and Tynset, Op Dovre, Lesja and Skjåk and Bu Hemsedal; MR Rauma and Sunndal, ST Oppdal, Meldal and Trondheim, NT Levanger. common in Öl and fairly common in Gtl, declining on the mainland; scattered in the eastern provinces from Klm to Nrk, Vsm and Upl, in Hls, central Dlr, central Jmt and in the large river valleys of Mpd and Ång; westwards rarer: eastern Sk (formerly also in the south and west), Bl Förkärla 1823, Sturkö 1983–91, SmI Eksjö and the valley of Emån, formerly more widespread in the north, Hl 3 localities, latest seen Fjärås 1955, BhG Askum 1994, Tanum 1931 and Tjärnö 1929, Vrm several localities; northernmost in LyL Stensele (Gunnarn). fairly common in EH, ES and PS , otherwise scattered to rare in the southern provinces north to St, PH and PK; further north in OP Oulu, rare in Kn, scattered in Ks (northern Kuusamo and southern Salla), SoL Pelkosenniemi (Suvanto). – Reported from D NJy Thy, Sjæ Gribskov and Thureby by Clausen (1931), but the specimens belong to V. riviniana. There are no vouchers for the reports from N SF Luster (Lid & Lid 2005) and S Dls Ånimskog (Kindberg & Sundblad 1854).
N, E and C Europe, the Caucasus, C Asia, Siberia east to the Sea of Okhotsk and Sakhalin.
Habitat. Open to fairly open, dry places, mainly on sand or gravel; calciphilous. Sandy grass heath, esker slopes, open sandy pine woods, limestone pavement with sandy moraine cover, dunes with more or less closed vegetation, scree slopes; sometimes in slightly more damp places on clayey sand.

9B. subsp. relicta Jalas      Map      Ill.

Jalas, Ann. Bot. Soc. Zool.-Bot. Fenn.’Vanamo’ 24(1): 70 (1950). – Type: F EnL Enontenkiö (Saana), VII. 1935, Roivainen (H) lectotype, sel. by Jonsell, ****..

D Laplands-Viol. F pahtahietaorvokki. N kalkfiol. S lappviol.

Literature. Aronsson 1999, Ryttäri & Kettunen 1997.

Indumentum always present, of 0.05–0.15 mm long, usually slightly downwards-pointing hairs. Basal leaves with petiole up to 4 cm; blade 9–20(–25) × 8–20 mm (summer leaves do not develop), 1–1.5 times as long as wide; base truncate or slightly cordate; apex obtuse. Aerial stems to 7 cm; summer stems not observed. Stem leaves (0–)1–3; petiole up to 10 mm; blade of middle stem leaves 9–18 × 7.5–15 mm, 1–1.3 times as long as wide, base truncate to cordate.
Pedicels to 6 cm. Upper sepals 4–4.5 × 1–1.2 mm, lateral ones 5–6.5 × 1.4–1.8(–2.1) mm (in both cases excluding the appendage); upper appendages 0.5–0.7 × 1–1.2 mm, lateral ones 0.5–0.7 × 1.3–2 mm. Corolla 10–19 mm high × 10–19 mm wide in front view. Petals violet blue; upper ones ovate to elliptic, 6–10 × 3–7 mm; spurred petal 12 × 8 mm excluding the spur; spur  light violet blue, 4.5–6 × 2.8–3.3 mm. Cleistogamous flowers not observed. Capsule 6.2–7.5 mm. Seeds 1.7–2.2 × 1.2–1.9 mm. – Early summer to mid-summer.
2n=20 (N MR, NNo).
Distribution. MBor–LAlp. Alt. Tr 1050 m. – MR Fræna (Trollkyrkja caves); scattered from northernmost SNo Meløy to eastern VFi Porsanger. LL Jokkmokk (4 localities in the Salohaure area), TL Jukkasjärvi (9 localities in the Torne träsk area). EnL Enontekiö (Saana, Pikku-Malla).
Endemic.
Habitat. Limestone (especially dolomite) cliffs and pavement, south-facing scree.

10. Viola reichenbachiana Jord. ex Boreau      Map      ill.

Boreau, Fl. centre France, ed. 3, 2: 78 (1857). – Described from France.
V. sylvestris Lam. (1779), nom. illeg.
V. canina var. silvatica Fr. (1828). – V. silvatica Fr. ex Hartm. f. (1841).

D Skov-Viol. F pyökkiorvokki. Fa . I . N lundfiol. S lundviol.

Literature. Clausen 1931, Rasmussen 1954, Ryttäri & Kettunen 1997, Stork 1970, 1971, Wind 1985, Marcussen et al. 2003.

Hemicryptophyte. Rhizomatous, caulescent perennial. Rhizome vertical, covered with numerous brown stipules, with a terminal leaf rosette. Rosette leaves 3–6(–8); stipules narrowly subulate, 7.5–11 mm, brown, with 7–11 slender fimbriae which are longer than the width of the stipule at the point of attachment; petiole to 12 cm, glabrous; blade ovate to oblong-ovate, 25–47 × 20–38 mm, 1.1–1.5 times as long as wide, pure green, with scattered, fairly long hairs on the upper surface; margin crenate with 15–20 obtuse teeth or near the base with forwards-pointing teeth; base cordate to deeply cordate; apex acute or obtuse. Aerial stems developing before chasmogamous flowering, erect or ascending, to 30 cm, glabrous. Stem leaves 3–9; stipules narrowly subulate, 7–10 mm, green but turning brown with age, with slender fimbriae longer than the width of the stipule at the point of attachment; petiole to 5 cm, decreasing in length towards the top of the stem, glabrous; blade of middle stem leaves ovate to oblong-ovate, 25–55 × 20–35 mm, 1.2–1.6 times as long as wide, pure green, with scattered, fairly long hairs on the upper surface; margin crenate with 10–15 obtuse teeth or near the base with forwards-pointing teeth; base cordate to deeply cordate; apex acute.
Chasmogamous flowers scentless, from the middle or upper part of the aerial stems. Pedicels glabrous, to 10 cm, longer than the subtending leaves; bracteoles subulate, in the upper half of the pedicel. Sepals lanceolate, acute, upper ones 4.5–6.7 × 1.1–1.8 mm, lateral ones 4–6.5 × 0.8–2 mm (in both cases excluding the appendage); appendage suborbicular to truncate, on upper sepals 0.4–0.8 × 0.8–1.5 mm, on lateral ones 0.3–0.8 × 0.6–1.5 mm, all 0.04–0.18 times as long as the rest of the sepal. Corolla 17–22 × 12–18 mm in front view, 1.15–1.5 times as high as wide, flat in front view. Petals red-violet to blue, whitish at the base (very rarely entirely white), margin not or only slightly overlapping; upper petals recurved, narrowly obovate, 10–15 × 3.5–6 mm, 2.3–3.4 times as long as wide; lateral petals narrowly obovate, 12–15 × 4–6 mm, 2.3–3.2 times as long as wide, with hyaline hairs at the throat; spurred petal slightly concave, 11–15 × 5–8 mm excluding the spur, 1.5–2.3 times as long as wide, without or with few and indistinct veins at the throat; spur violet or white, cylindric, straight, pointed, 4.5–6.5 × 2–3 mm, 1.8–2.7 times as long as wide, 6–14 times as long as the sepal appendages. Style papillose near the tip. Cleistogamous flowers 3–4 mm, sepal appendages all of the same size. Capsule ovoid, trigonous, obtuse, 7–10 mm, glabrous, explosive. Seeds ovoid, 1.8–2.1 × 1–1.3 mm, pale to light brown; elaiosome small. – Early spring to mid-spring (chasmogamous flowers),  mid-spring to mid-summer (cleistogamous flowers).
2n=20 (D Sjæ, F A, S Sk). - [2n = 20]
Distribution. Nem–BNem. – D common in the islands, ØJy and eastern SJy; NJy scattered in eastern Vendsyssel and the western Limfjorden area; VJy at least Nørrehede, Sevel, Esbjerg and Lunde. S fairly common in lowland Sk and coastal Bl, southernmost Hl, and in Öl and central Gtl;, rare in Klm, SmI (mainly near Vättern), Vg (mainly Kinnekulle and northern Billingen), Ög, Dls and Srm; BhG Göteborg 1890, Upl Frötuna and Söderby-Karl (spontaneous), Lovö 1916, Vaxholm 1925 (probably brought in with garden plants or seed). F A Lemland (Nåtö, two sites). – Also reported from southeastern Vsm (Malmgren 1982), but no specimens have been seen.
W Eurasia, from C Spain and the British Isles east to Estonia and Greece, N Turkey and the Caucasus; in Crete (distinguished as V. idaea) probably extinct. Reports from the Canary Islands (and probably also those from Algeria and Morocco) were based on V. riviniana.
Habitat. Nutrient-rich and usually lime-rich mull soil on shady, moderately dry to moderately damp places. – Herb-rich deciduous woodland, moist woodland with Ulmus and Fraxinus, Corylus groves, wooded meadows; apophytic in hedges, parks and gardens.
Biology. The chasmogamous flowers can remain open for up to 15 days without signs of senescence (Beattie 1969).
Hybridization. Hybrids of Viola reichenbachiana are known with V. canina, V. mirabilis, V. pumila, V. riviniana, V. rupestris subsp. rupestris, V. stagnina and V. uliginosa.
Similar taxa. When not flowering, Viola reichenbachiana and V. riviniana (11) are hard to tell apart (for diagnostic characters, see the latter).

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11. Viola riviniana Rchb.      Map      ill.

Reichenbach, Iconogr. bot. pl. crit. 1: 81 (1823). – Described from Germany (Dresden).

D Krat-Viol. F metsäorvokki. Fa dimm blákolla. I skógfjóla. N skogfiol. S skogsviol.

Literature. Clausen 1931, Rasmussen 1954, Wind 1985, Marcussen et al. 2003.

Hemicryptophyte. Rhizomatous, caulescent perennial. Rhizome vertical, normally branching at (or occasionally below) the soil surface, covered with numerous brown stipules, with a terminal leaf rosette. Rosette leaves 3–5; stipules subulate, 8–12.5 mm, brown, with 5–8 coarse fimbriae which are shorter than the width of the stipule at the point of attachment; petiole to 12 cm, glabrous or sometimes puberulent; blade ovate, broadly ovate or reniform, 25–45 × 22–38 mm, 1–1.4 times as long as wide, pure green, with rather numerous short hairs on the upper surface, glabrous or with few hairs along the veins on the lower surface; margin crenate with 15–20 obtuse teeth or near the base with forward-pointing teeth; base cordate to deeply cordate; apex acute or obtuse. Aerial stems developing before chasmogamous flowering, erect or ascending, to 30 cm, glabrous, papillose, slightly hairy at the nodes or sometimes puberulent throughout. Stem leaves 3–9; stipules subulate, 6–11 mm, green but turning brown with age, with fimbriae shorter than the width of the stipules at the point of attachment; petiole to 6 cm, decreasing in length towards the top of the stem, glabrous or sometimes puberulent; blade of middle stem leaves ovate to broadly ovate, 30–50 × 30–42 mm, 1–1.3 times as long as wide, pure green, with rather numerous short hairs on the upper surface, glabrous or with few hairs along the veins on the lower surface; margin crenate with 15–20 obtuse teeth or near the base with a forward-pointing tooth; base cordate to deeply cordate; apex acute.
Chasmogamous flowers scentless, from the middle or upper part of the aerial stems. Pedicels glabrous or sometimes puberulent, to 10 cm, longer than the subtending leaves; bracteoles subulate, in the upper half of the pedicel. Sepals lanceolate, acute, upper ones 5–8 × 1.1–1.7 mm, lateral ones 5.5–8.5 × 1.7–2.5 mm (in both cases excluding the appendage); appendage suborbicular to truncate, on upper sepals 0.8–1.8 × 0.6–1.3 mm, on lateral ones 1.1–2.5 × 1.3–2 mm, all 0.15–0.35 times as long as the rest of the sepal. Corolla 17–25 × 17–25 mm, 0.9–1.1 times as high as wide, flat in front view. Petals violet, whitish at the base, clearly overlapping; upper petals recurved, broadly obovate, 13–18 × 6–9 mm, 1.8–2.4 times as long as wide; lateral petals narrowly obovate, 14–18 × 6–9 mm, 1.9–2.4 times as long as wide, with hyaline hairs at the throat; spurred petal slightly concave, 13–17 × 7.5–10 mm excluding the spur, 1.4–2 times as long as wide, with 2–5 distinct veins at the throat; spur white or rarely violet, thick, straight or upcurved, blunt, 5–7 × 3–4 mm, 1.5–2 times as long as wide, 3–7 times as long as the sepal appendages. Style papillose near the tip. Cleistogamous flowers 3–4 mm, lower sepal appendages longer than the upper ones, 0.12–0.2 mm. Capsule ovoid, trigonous, obtuse, 8–12 mm, glabrous, explosive. Seeds ovoid, 1.8–2.1 × 1.1–1.3 mm, pale to light brown; elaiosome small. – Early spring to mid-spring, occasionally autumn (chasmogamous flowers), mid-spring to mid-summer (cleistogamous flowers).
2n=35–40 (F A), c. 40 (F EH), 40 (D Sjæ). – [2n=40]
Distribution. Nem–NBor. Alt. N Bu 980 m. – D mostly common, but scattered (locally even absent) in westernmost Jylland. N common in the lowlands north to Tr Tromsø, Karlsøy and Nordreisa, but rare or absent in the continental parts of the valleys (He, Op, Bu). S common north to central Vrm, central Dlr and Ång, scattered to rare further north and inland to Jmt and Nb; ÅsL Dorotea (Månsberget), Fredrika (Klippen) and Vilhelmina (Lilla Stalonberget), LyL Lycksele (Skrattabborrtjärn), LyL Malå (Tjamstaberget), Stensele (Kyrkberget), PL Arjeplog (Tjäutjanåive), LL Jokkmokk (Juopmotjåkko and Kanisvaratj). F very common in the southern boreal zone north to EP, southern PH, central PS and PK, further north scattered to southwestern PeP; isolated occurrences in Ks northern Kuusamo. Fa common (not known from Lítla Dímun). I scattered in IVe in the Snæfellsnes and Reykjanes peninsulas and in IAu from Reyđarfjörđur to Hérađsflói (isolated in northernmost Finnafjörđur); rare in westernmost coastal ISu, INo from Fjörđur to Flateyjardalsheiđi, and INv Bessárdalur.
Europe, east to the Moscow basin in W Russia, south to the mountains of Greece and the Iberian peninsula; mountains of NW Africa (Algeria and Morocco); Madeira; a deviant race in the Canary Islands.
Habitat. Moist to moderately dry, modestly to very nutrient-rich soil in woodland. – Glades in deciduous woodland and spruce forest, oak scrub, calcareous pine forest, in the mountains in south-facing scree; occasionally in dry grassland or in shady, mossy forest, in the latter case usually not flowering.
Biology. Propagation with adventituous root buds occurs in some individuals; it seems to be correlated with presence of B chromosomes (Valentine 1950). Although such vegetative propagation can be conspicuous in culture, it does not appear to be important in nature or to affect the genetic composition of populations (Auge et al. 2001).
Variation. Viola riviniana is fairly variable in leaf shape and size, outline of the corolla, petal colour and shape and size of the spur. The spur is typically white, but may be as dark as the rest of the corolla. Usually the plants have scattered hairs only on the upper surface of the leaves, but variants which are densely short-hairy also on the stems and peduncles occur; such plants can be reminiscent of V. rupestris which, however, has much shorter hairs. Besides, height and vigour vary according to the habitat conditions; specimens from exposed sites tend to be smaller and more compact than those growing in shady places.
A variant with purple leaves and hairy stems is sometimes cultivated (incorrectly referred to the NE American V. labradorica Schrank).
Norden via two main routes after the last glaciation: the first from a glacial refugium west of the Alps and into Norden west of the Scandes (i.e. the Atlantic coast of N), possibly via a now submerged North Sea continent; the second from a glacial refugium east of the Alps and into Norden east of the Scandes (southeastern N, S and F); F may have been colonised by a different subpopulation, however.
Taxonomy. Viola riviniana has usually been considered a tetraploid based on x=10. However, since x=10 is itself a palaeotetraploid number the species is better considered an octoploid.  Apparently it originated from hybridization between V. reichenbachiana and an unknown taxon that was also involved in the origin of V. canina (2n=40; Valentine 1962) but no longer occurs in Europe.
A study of isozyme and chloroplast DNA variation (Marcussen et al. 2003) suggests that V. riviniana colonized Norden via two main routes after the last glaciation: the first from a glacial refugium west of the Alps and into Norden west of the Scandes (i.e. the Atlantic coast of N), possibly via a now submerged North Sea continent; the second from a glacial refugium east of the Alps and into Norden east of the Scandes (southeastern N, S and F); F may have been colonised by a different subpopulation, however. Harmaja (2003a) reported, in addition to the normal chromosome number 2n=40, four populations with 2n=30 or c. 30 from F V Lohja and U Siuntio. Seed set and/or pollen was apparently normal. The plants deviated by having a smaller corolla with narrower, non-overlapping petals, coloured spur and slightly elongated leaves; the stipules had only few, short cilia. They are thus in some (but not all) respects intermediate between V. riviniana and V. reichenbachiana
Hybridization. Hybrids of Viola riviniana are known with V. canina, V. elatior, V. mirabilis, V. pumila, V. reichenbachiana, V. rupestris (both subspecies), V. stagnina and V. uliginosa.
Similar taxa. Viola riviniana from dry, exposed places is similar to V. rupestris, but differs in the shape of the stipules (see also above under Variation). V. riviniana from shady habitats, especially plants with dark spurs, can be very similar to V. reichenbachiana but generally has wider stipules with shorter fimbriae, more rounded leaves and longer sepal appendages.

12. Viola mirabilis L.       Map      ill.

Linnaeus, Sp. pl.: 936 (1753). – Type: Linnaean Herbarium 1052.15 (LINN) lectotype, sel. by Nikitin, Novit. Syst. Pl. Vasc. 31: 217 (1998).

D Forskelligblomstret Viol. F lehto-orvokki. Fa . I . N krattfiol. S underviol.

Literature. Clausen 1931, Rasmussen 1954, Wind 2001.

Hemicryptophyte. Rhizomatous, caulescent perennial. Rhizome vertical, ± branched, covered with numerous withered stipules, with a terminal leaf rosette. Rosette leaves 1–3; stipules subulate, 14–22 mm, brown to pale brown, with entire margin; petiole to 20 cm, with an abaxial line of short, hyaline, patent hairs; blade reniform, orbicular or cordate, 20–70 × 30–75 mm, as long as wide or wider than long, pure green, with scattered hairs; margin crenate with 10–25 obtuse, shallow teeth; base deeply cordate to truncate; apex obtuse, acute or apiculate. Aerial stems developing at time of chasmogamous flowering, erect, to 30 cm, with an abaxial line of short, hyaline, patent hairs. Stem leaves normally 3, one at the middle of the stem, two close together at the top; stipules broadly subulate, 3–20 mm, green or brown, shortly fimbriate with fimbriae much shorter than the width of the stipule; petiole of the middle stem leaf  to 10 cm, that of the upper leaves to 1 cm (sometimes almost absent); blade reniform, orbicular or cordate, 20–60 × 25–65 mm, as long as wide or wider than long; pure green, with scattered hairs; margin crenate with 10–25 obtuse, shallow teeth; base cordate to almost truncate; apex acute to obtuse.
Chasmogamous flowers scented, from the leaf rosettes or occasionally from the lowermost stem node. Pedicels glabrous, to 10 cm, shorter than the rosette leaves; bracteoles brown, above the middle of the pedicel. Sepals lanceolate, acute, 6–12.5 × 1–4 mm (excluding the appendage), appendage semicircular or truncate, 1–4 × 1–4 mm, 0.15–0.35 times as long as the rest of the sepal. Corolla cup-shaped in front view. Petals violet to pale violet, whitish at the base (rarely entirely white); upper petals recurved, obovate, 8.5–18 × 3–9.5 mm; lateral petals narrowly obovate, 8–18 × 3.5–8.5 mm, with hyaline hairs at the throat; spurred petal slightly concave, 8–17.5 × 3.5–8.5 mm excluding the spur, 1.4–2.8 times as long as wide; spur white, thick, blunt, straight, 3–8 × 2–3.5 mm, (0.5–)2–3(–5) times as long as the sepal appendages. Style not papillose. Cleistogamous flowers on aerial stems, conspicuous, 8–16 × 3–6 mm. Capsule ovoid, trigonous, obtuse, 8–14 × 2.5–7 mm, glabrous, explosive. Seeds ovoid, c. 2.5 × 1.5 mm, pale to light brown; elaiosome small. – Early spring (chasmogamous flowers) and mid-spring to mid-summer (cleistogamous flowers).
2n=20 (D Sjæ, S Sk). – [2n = 20]
Distribution. Nem–MBor(–NBor). Subcontinental. Alt. N Op 1260 m. – D rare and declining, now only in central Sjæ (7 localities), FyL Torup Krat and ØJy (4 localities); formerly more widespread in Sjæ, eastern ØJy and northeastern FyL and also known from NJy (2 localities), FyL Langeland (Rifbjerg), LFM Lolland (Købelev Skov) and Brn (3 localities). N fairly common in the southeast from AA Tvedestrand and VA Åseral; west of the Scandes from the head of the fjords in Ho Eidfjord and Voss north to Tr Lavangen. S mostly fairly common north to central and eastern Vrm, central Dlr and coastal Ång as well as in parts of lowland Jmt (but almost absent from Hl, western SmI and southern Dls); fairly rare to rare further north to LyL and Vb; LL Jokkmokk (5 localities). F A rather common; in the mainland a rather continental distribution north to southwestern PeP, with centres in EH, PS, PK and central Kn.
Eurasia from the E Pyrenees, Massif Central, the S Alps and Norden east to the Baikal area; the Caucasus (var. mirabilis). In the Amur region, NE China, Korea and N Japan represented by var. subglabra Ledeb. (V. brachysepala Maxim.).
Habitat. Moderately shady places in forest and groves on well-drained, deep, nutrient-rich and usually base-rich soil; thermophilous. – Deciduous woodland (in the south mainly with Corylus in former wooded meadows), dry and herb-rich forests (typically with Pulmonaria, Tilia, Hepatica, Actaea, Carex digitata), spruce forest with a rich field layer, rapids in forest streams, warm screes, ravines and bouldery slopes; more rarely in drier and more open habitats such as calcareous pine forest and calcareous juniper heath; in central S sometimes on debris from mining, otherwise not hemerophilous.
Biology. The chasmogamous flowers of Viola mirabilis are not “sterile”, as often stated in the literature; pollination success over 50% has been reported from F (Mattila & Salonen 1995), but may vary with site and year. Failure to set seed would have to result from other factors, such as paucity of pollinators. – V. mirabilis can spread with adventitious root buds.
Variation. Chasmogamous flowers are occasionally produced also in the lower nodes of the aerial stems. Subglabrous plants lacking the characteristic abaxial stripe of hairs on the petioles occur scattered throughout Norden. Neither character should alone be taken as evidence of hybridization.
Hybridization. Hybrids of Viola mirabilis are known with V. canina, V. reichenbachiana, V. riviniana and V. rupestris subsp. rupestris.

13. Viola uliginosa Besser       Map      ill.

Besser, Prim. fl. Galiciae austriac. 1: 169 (1809). – Described from Poland (Krakow).

D Sump-Viol. F luhtaorvokki. Fa . I . N sumpfiol. S sumpviol.

Literature. Albinsson 2000, Aronsson 1999, Clausen 1931, Hæggström et al. 1985, Kääntönen 1975, Laine 1951, Rasmussen 1954, Ryttäri & Kettunen 1997, Wind 2006.

Hemicryptophyte. Rhizomatous, acaulescent perennial. Rhizome horizontal, richly branching below the soil surface, forming subterranean runners, covered with numerous brown stipules, with terminal leaf rosettes. Rosette leaves 2–4; stipules adnate to the petiole in the lower part, narrowly subulate, 7.5–11 mm, light brown to brown, entire or minutely toothed; petiole to 12 cm, glabrous; blade ovate to oblong-ovate, 30–70 × 25–50 mm, 1–1.5 times as long as wide, pure green, with few, scattered, hyaline hairs on the upper surface, glabrous on the lower surface; margin crenate with 15–20 obtuse teeth or near the base with forwards-pointing teeth; base cordate to deeply cordate; apex acute or obtuse.
Flowers scentless, from the rhizome. Pedicels glabrous, to 20 cm, longer than the subtending leaves at flowering time; bracteoles subulate, in the upper half of the pedicel. Sepals acute, upper ones lanceolate to elliptic, 3.5–5.5 × 1.3–2 mm, lateral ones narrowly to broadly ovate, 3.8–5.5 × 2–3.2 mm (in both cases excluding the appendage); appendage suborbicular to truncate, on upper sepals 0.5–1.6 × 0.6–1.4 mm, 0.15–0.5 times as long as the rest of the sepal, lateral ones 1–2.8 × 1.6–2.7 mm, 0.17–0.25 times as long as the rest of the sepal. Corolla 30 × 20 mm, 1.5 times as high as wide, flat in front view. Petals violet; upper petals recurved, oblanceolate with obtuse, truncate or retuse tip, 15–20 × 6.5–9 mm, 1.8–2.6 times as long as wide; lateral petals oblanceolate with obtuse, truncate or retuse tip, 18–25 × 6–9 mm, 2.1–2.8 times as long as wide, without or with only a few hyaline hairs at the throat; spurred petal 16–20 × 6–9 mm excluding the spur, 1.9–2.7 times as long as wide; spur violet, cylindric, straight, 3–5 × 2–3.5 mm, 1.1–1.8 times as long as wide, 2.5–6 times as long as the sepal appendages. Style not papillose. Capsule ovoid, trigonous, obtuse, 8–11 mm, glabrous, explosive. Seeds ovoid, 1.4–1.6 × 0.65–0.8 mm, pale to light brown; elaiosome small. – Early spring to mid-spring (chasmogamous flowers).
[2n=20]
Distribution. Nem–BNem. – D Brn Vallensgård Mose; formerly also Ekkodalen, Åremyr and Ølene. S Sk Allerum, Vä and Össjö, formlery a further 6 localities, Bl Kristianopel, Öl Vickleby (Karlevi), last seen in 1952, Klm c. 60 localities in four river systems in the southwest (Brömsbäcken, Hagbyån, Halltorpsån and Ljungbyån), Hl Hunnestad and Stamnared, Ög Brunneby, Lönsås, Västra Harg and Västra Ny (formerly), Nrk Bo (Fyllinge), Srm Björnlunda (formerly) and Åker, Vsm Kungsåra, Upl Estuna, Täby and several localities along Jumkilsån; c. 100 localities in the lower reaches of Dalälven in Upl and Gst. F known from c. 20 places in the south (mostly very small populations): A Hammarland and Kökar, V Vihti, U Hanko, Mäntsälä and Vantaa, ES Valkeala and St Vammala, and (extinct) U Hyvinkää and Kauniainen, EH Hämeenlinna, Kuusankoski and Tampere (Ryttäri & Kettunen 1997).
Outside Norden from E Germany east to W Russia and south to Slovenia; declining throughout.
Habitat. Permanently wet or temporarily inundated, bare, nutrient-rich soil in slightly shady habitats. - Shores of streams and rivers, Alnus glutinosa swamps; often abundant.
Biology. There are no reports of cleistogamous flowers, although flower production has been studied both in Nordic and C European populations, and it seems likely that the capacity for cleistogamy has been lost in this species (Gams in Hegi 1925).
Taxonomy. Due to its morphological distinctness, Viola uliginosa has traditionally been referred to a subsection of its own, Repentes (Kupffer) W. Becker (Valentine et al. 1968). Karyological studies of artificial (Bamford & Gershoy 1930, Harvey 1966) and natural hybrids (Kuta 1978) have shown that V. uliginosa is chromosomally at least as closely related to European species of subsect. Rostratae as these are to their morphologically similar relatives in eastern N America. Systematically important traits such as style shape and the chromosome number 2n=20 suggest a close relationship between V. uliginosa and subsect. Rostratae or subsect. Viola.
Hybridization. Hybrids of Viola uliginosa are known with V. canina, V. reichenbachiana, V. riviniana and V. stagnina.

14. Viola stagnina Kit.       Map      ill.

Kitaibel in Schultes, Oestr. Fl., ed. 2, I: 426 (1814). – Described from ***.
V. persicifolia auct., nom. rejic. prop.

D Rank Viol. F rantaorvokki. Fa . I . N bleikfiol. S strandviol.

Literature. Clausen 1931, Klaveness 1974, Rasmussen 1954, Ryttäri & Kettunen 1997, Røren 1993, Røren et al. 1994.

Hemicryptophyte. Rhizomatous, caulescent perennial. Rhizome vertical, branching below or at the soil surface, covered with numerous brown stipules; terminal leaf rosette absent. Aerial stems erect, normally to 25 cm, glabrous or with few, scattered, small hairs. Stem leaves up to 10; stipules narrowly lanceolate, 5–22 mm, usually not longer than the petiole, green, hairy, with few coarse teeth; petiole to 2 cm, glabrous except for hyaline hairs at the base; blade narrowly ovate to lanceolate, 20–40 × 5–20 mm, 2–4 times as long as wide, light green, with scattered, hyaline hairs on the upper surface, glabrous on the lower surface; margin crenate with 10–15 obtuse teeth or near the base with forwards-pointing teeth; base truncate or slightly cordate, markedly decurrent onto the petiole; apex acute.
Chasmogamous flowers scentless, from the middle or upper part of the aerial stems. Pedicels glabrous, to 3 cm, shorter than the subtending leaves; bracteoles subulate, in the upper half of the pedicel. Sepals lanceolate, acute, 4.5–10 × 1.3–2.5 mm (excluding the appendage); appendage suborbicular to truncate, 0.6–2.5 × 1.3–2.5 mm, 0.1–0.3 times as long as the rest of the sepal. Corolla 20 × 15 mm, 1.3 times as high as wide, flat in front view. Petals white with light violet veins; upper petals recurved, obovate, obtuse, 6–13 × 3.5–8 mm, 1.8–2 times as long as wide; lateral petals narrowly obovate, obtuse, 10–13 × 4–6 mm, 1.8–2.2 times as long as wide, with hyaline hairs at the throat; spurred petal slightly concave, 8–16 × 4–8 mm excluding the spur, 1.9–2.1 times as long as wide; spur light green to yellow-green, sac-like, 2–4 × 2–3.5 mm, 0.9–1.1 times as long as wide, 2.5–3.5 times as long as the sepal appendages. Style papillose at the tip. Cleistogamous flowers 4–5 mm. Capsule ovoid, trigonous, acute, 6–8 mm, glabrous, explosive. Seeds ovoid, 1.4–1.6 × 0.65–0.8 mm, pale to light brown; elaiosome small. – Late spring to early summer (chasmogamous flowers), mid-summer (cleistogamous flowers).
2n=20 (N Ak 4, Bu 10). – [2n = 20]
Distribution. Nem–BNem(–SBor). – D ØJy only Paderup (formerly 5 localities), Sjæ c. 8 localities (formerly scattered), Brn only Vallensgård Mose (formerly c. 10 localities); extinct in FyL (known from c. 6 localities, latest Reveldrup 1895) and LFM (c. 6 localities, latest Borgø 1884). N only in the southeast, rare and primarily in connection with the large lakes and rivers: Vansjø (Øf Sarpsborg, Rygge, Råde, Moss, Våler), Øyeren (Øf Trøgstad, Ak Enebakk, Rælingen, Skedsmo, Nittedal, Fet), Ak Ullensaker, Mjøsa (He Stange, Hamar), the river Glomma (He Nord-Odal, Kongsvinger), Tyrifjorden (Bu Lier, Hole, Ringerike, Modum), Bu Nedre Eiker. S fairly common on the shores of Vänern in Vg, Dls and Vrm, elsewhere scattered north to southern Vsm and the lower reaches of Dalälven in Upl, Gst and Dlr (but rare or absent from much of the southwest); further north Dlr the lake Siljan. F mainly in A and the River Kokemäenjoki water course from EH Hattula and Pälkäne to St Kokemäki; elsewhere rare north to EH Jämsä, ES Rantasalmi and PK Rääkkylä (extinct); many localities disappeared. – Also reported from N Op Østre Toten (Lid & Lid 2005; no specimens have been seen) and S Jmt Fors 1993 (Berglin 1998; voucher disappeared).
From the British Isles and northern Spain east to W Siberia, although most Siberian records are based on misidentified V. pumila (Eckstein et al. 2006).
Habitat. Temporarily flooded shores of lakes, streams and fens usually on base-rich but nutrient-poor substrate. Usually in S- or W-exposed situations; thermophilous and light-demanding. – Gravelly to stony bare shores, rock fissures close to the water, wet and moist meadows on rather rich humus soils, low grassland, sometimes in open wooded fens. Sensitive to competition and in grassland localities dependent on mowing or grazing. In later decades declining all over Norden due to eutrophication, overgrowth, water regulation and ditching.
Biology. The number of flowering plants is very small on many sites but may vary greatly between years. Extinct populations are sometimes restored from the persistent seed bank if the vegetation cover has been disturbed (Woodell 1965, Rowell et al. 1982, Rowell 1984). – Viola stagnina can spread by adventitious root buds.
Taxonomy. Viola stagnina has usually been considered a diploid based on x=10, but this number is in fact palaeotetraploid. Apparently it has been involved in the polyploid origin of both V. canina and V. pumila (Moore & Harvey 1961).
The name Viola persicifolia Schreb. has long been used for this species. This name has, however, been repeatedly used also for V. elatior and V. pumila (Eckstein et al. 2006); most probably it belongs to V. elatior (Rauschert 1973), but a formal typification is still lacking. Because of this ambiguity and uncertainty the name V. persicifolia should be rejected (see Kirschner & Skalický 1989), and the later name V. stagnina should be used for the species treated here.
Hybridization. Hybrids of Viola stagnina are known with V. canina, V. elatior, V. pumila, V. reichenbachiana, V. riviniana and V. uliginosa.

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15. Viola canina L.       Map      ill.

Linnaeus, Sp. pl.: 935 (1753). – Type: Linnaeus, Lapland Herbarium 277 (LAPP), lectotype, sel. by Nikitin, Bot. Zhurn. 80(7): 93 (1995).
V. montana auct., non L. (1753). – V. canina subsp. montana auct., non (L.) Hartm. (1841).
V. nemoralis Kütz. (1832). – V. canina subsp. nemoralis (Kütz.) Elven (2005), nom. illeg.

D Hunde-Viol. F aho-orvokki. Fa fjallablákolla. I týsfjóla. N engfiol. ängsviol.

Literature. Clausen 1931, Marcussen 2007, Rasmussen 1954.

Hemicryptophyte. Rhizomatous, caulescent perennial. Rhizome vertical, branching at or below the soil surface, covered with numerous brown stipules, terminal leaf rosette absent. Aerial stems ascending to erect, to 30 cm but often much smaller, glabrous. Stem leaves 4–7; stipules almost linear to lanceolate, upper ones to 30 mm, 0.3–1.7 times as long as the petiole, brownish or green, minutely toothed; petiole to 2.5 cm, decreasing in length towards the top of the stem, glabrous, shorter than the blade; blade ovate to oblong-ovate, 12–50 × 10–27 mm, 1–2 times as long as wide, deep green to grey-green; glabrous or with scattered hyaline hairs on the upper surface, glabrous or with few hyaline hairs along the veins on the lower surface; margin crenate with 15–20 obtuse teeth or near the base with forward-pointing teeth; base truncate, cordate or deeply cordate; apex acute or obtuse.
Chasmogamous flowers scentless, from the middle or upper part of the aerial stems. Pedicels glabrous, to 8 cm, longer than the subtending leaves; bracteoles subulate, in the upper half of the pedicel. Sepals lanceolate, acute, 5–8 × 1.9–2.5 mm (excluding the appendage); appendage suborbicular to truncate, 1.1–1.9 × 1.8–2.5 mm, 0.2–0.3 times as long as the rest of the sepal. Corolla 20 × 20 mm, as high as wide, flat in front view. Petals blue-violet to grey-violet, white at the base, rarely white; upper petals recurved, obovate, obtuse, 10–14 × 5–8 mm, 1.6–2.2 times as long as wide; lateral petals obovate, obtuse to truncate, 10–14 × 4–7 mm, 1.8–2.4 times as long as wide, with hyaline hairs at the throat; spurred petal 13–17 × 6–9 mm excluding the spur, 1.7–2.4 times as long as wide; spur light yellow to light green, cylindric, straight, 3–5 × 2–3 mm, 1.2–1.8 times as long as wide, 2–3.5 times as long as the sepal appendages. Style not papillose. Cleistogamous flowers 3–4 mm; sepal appendages all of the same size. Capsule ovoid, trigonous, obtuse (sometimes apiculate), 7.5–9 mm, glabrous, explosive. Seeds ovoid, 1.7–2.1 × 1–1.3 mm, light to dark brown; elaiosome small. – Spring to early summer (chasmogamous flowers), summer (cleistogamous flowers).
2n=40 (D Sjæ, N Ak 3, Bu 2, Øf, S Sk, Upl), c. 40 (N Ak 3, Bu, Øf). – [2n=40]
Distribution. Nem–MAlp. Alt. N Op 1580 m. – D formerly common throughout, but declining and now scattered to rare in eastern and southeasternmost Jylland and in FyL, LFM and southern Sjæ; everywhere more common on nutrient-poor soils N common throughout. S common north to PL and Nb, scattered in northern Lapland and in agricultural areas in the south. F common north to KiL and SoL, scattered in InL, rare in northwestern EnL. Fa Nólsoy and Sandoy. I common in large parts of the lowlands, but rare in central and eastern ISu and southern IAu; IMi fairly common in the north, rare in the south.
Outside Norden from N Spain and the British Isles east to the Baikal area; southern Greenland (perhaps introduced).
Habitat. Sunny to moderately shady, dry to slightly moist, moderately nutrient-rich to nutrient-poor, more or less humus-rich mineral soil. – Heathland, grazed or mown grassland, slopes, white dunes, rock ledges, open woodland, forest margins; also roadsides, road cuttings, railway banks, gravel pits, etc. In the north mainly in the littoral vegetation of lakes, rivers and brooks, and in scree.
Biology. At least some populations of V. canina have the capacity to spread by adventitious root buds.
Variation. Viola canina is a polymorphic species. In northern Europe, two major variants are traditionally distinguished (see below) and two subspecies have been recognized (e.g. Valentine et al. 1968), said to differ in habit, stipule size, general leaf shape, flower colour, habitat ecology and distribution (see Marcussen 2007 for a survey).
Entity 1 (usually called subsp. canina; D Hunde-Viol, F pikkuaho-orvokki, I týsfjóla, N vanlig engfiol, S ängsviol) is said to be ascending and have middle stem leaves with stipules less than 1/2 or 1/3 (depending on the literature source) as long as the petiole, their blades less than twice as long as wide, with concave margins and cordate base. Plants referred to this entity are usually reported from dry meadows and warm slopes, and more frequently in the south.
Entity 2 (usually called subsp. montana, but see under Taxonomy below ; D Bjerg-Viol, F isoaho-orvokki, I urðafióla, N lifiol, S norrlandsviol) is said to be erect and have middle stem leaves with stipules more than 1/3 or 1/2 (depending on the literature source) as long as the petiole, their blades about twice as long as wide or longer, with straight to convex margins and subtruncate base. Plants referred to this entity are often reported from moister and more shady habitats, and also from north and east of the range of entity 1.
The two entities have been reported to be entirely interfertile (Schmidt 1961, Valentine 1962), and “intermediate” specimens that do not fit the description of either are frequent.
In a comparative growth experiment (Bergdolt 1932), stipule size and shape of V. canina could be manipulated by altering the availability of water and nutrients, and leaf-blade shape and texture by altering the light intensity. Plants cultivated under dry conditions developed “considerably” smaller stipules, while plants getting nitrogen fertilizer, high air concentration of CO2 and long-day light treatment developed larger stipules. Also, under strong UV irradiation the plants would develop leaves with a fleshy texture due to an additional row of palisade mesophyll. Plants having this feature, along with small size and creeping or ascending stems, are characteristic of the white dunes at the North Sea and Kattegat in D, southern S and southern N. Thus, many features considered diagnostic of the subspecies of V. canina may be induced by habitat factors.
A morphometric examination of V. canina in N (Marcussen 2007) showed (1) continuous variation in the diagnostic characters, (2) that some of the diagnostic characters are inapplicable due to seasonal variation (e.g. ratio stipule length/petiole length, varying with a factor of 6 within individuals) or because the observed variation does not fit the variation described in the literature (e.g. length/width ratio in the leaf-blade) or both, and (3) lack of geographically structured variation. The study concluded that the two subspecies should not be upheld in N. – In the Norwegian material, misdeterminations of V. canina × riviniana (and even V. riviniana) as V. canina ssp. canina were frequent, and may in fact have formed the concept of ssp. canina. This would explain why “subsp. canina” seems to closely follow the distribution of V. riviniana, at least in Norway.
The situation in the rest of Norden may well be different, and similar studies of the material from D, S and F would be welcome; at present, however, there is little evidence to support the subspecies of V. canina, and they are therefore not upheld here; a similar conclusion has been reached for the species in Russia (Nikitin 1998).
The tradition of splitting Viola canina into two subspecies may be due to a misunderstanding (Nikitin 1995). Linnaeus (1753) delimited his V. canina widely; the epithet “canina” referred to the great variation within the species, which included the taxa now known as V. canina, V. riviniana, V. reichenbachiana and V. rupestris (Becker 1917, Nikitin 1995). For V. montana L., on the other hand, the citation of references and specimens in the Linnean Herbarium indicate that Linnaeus had in mind the species today considered as V. elatior Fries; he named it montana based on a mislabelled specimen from “Lappland” collected by D. Solander (one of his students). The fact that V. elatior does not occur in northern S is apparently the reason why the name V. montana was misapplied by later authors.
Taxonomy. Viola canina has usually been considered a tetraploid based on x=10. However, since x=10 is itself a palaeotetraploid number the species is better considered an octoploid. Apparently it originated from hybridization between V. stagnina and an unknown taxon that was also involved in the origin of V. riviniana (2n=40; Valentine 1962) but no longer occurs in Europe. In turn, V. canina has probably been involved in the origin of the SW European endemic V. lactea Sm. (2n=58; Moore & Harvey 1961).
Hybridization. Hybrids of Viola canina are known with V. mirabilis, V. pumila, V. reichenbachiana, V. riviniana, V. rupestris (both subspecies), V. stagnina and V. uliginosa.
Similar taxa. Viola canina is similar to V. riviniana (11) in flower colour and flowering time, but V. riviniana rhizomes have a terminal rosette, and the leaves are not elongated (just a little longer than wide) and have a more strongly cordate base. V. stagnina (14) is similar to V. canina in build (no terminal rosette) and both have elongated leaves, but V. stagnina has truncate leaf-bases, and white or very pale bluish flowers with a short, greenish spur. – Hybrids with these two species are fairly common; they are variable, but completely sterile (see the hybrids for more differences).

16. Viola pumila Chaix       Map      ill.

Chaix in Villars, Hist. pl. Dauphiné 1: 339 (1786). – Described from France.

D Dværg-Viol. F alvariorvokki. Fa . I . N dvergfiol. S dvärgviol.

Literature. Persson 1969, Sterner 1938, 1986.

Hemicryptophyte. Rhizomatous, caulescent perennial. Rhizome vertical, branching at or below the soil surface, covered with numerous brown stipules; terminal leaf rosette absent. Aerial stems ascending, to 15(–20) cm, glabrous. Stem leaves 3–7; stipules narrowly lanceolate or oblanceolate, those of the upper leaves to 30 mm, 0.8–2 times as long as the petiole, green with distinctly dark veins, entire or with a few coarse teeth; petiole to 3 cm, shorter towards the top of the stem, glabrous, shorter than the blade, 0.5–1.3 times as long as the stipules; blade of middle and upper leaves narrowly ovate to narrowly lanceolate, 15–40 × 5–17 mm, 2–3.5 times as long as wide, dark green, glabrous; margin faintly crenate with 8–12 obtuse, low teeth or near the base with forwards-pointing teeth; base cuneate, narrowly decurrent onto the petiole; apex acute to obtuse.
Chasmogamous flowers scentless, from the middle or upper part of the aerial stems. Pedicels glabrous, to 10 cm, longer than the subtending leaves; bracteoles subulate, in the upper half of the pedicel. Sepals lanceolate, acute, upper ones 5–7 × 1–2 mm, lateral ones 5–8 × 1.5–2.5 mm (in both cases excluding the appendage); appendage suborbicular to truncate, in upper sepals 0.9–1.6 × 0.7–1.3 mm, in lateral sepals 1–2 × 1.5–2.2 mm, all 0.16–0.33 times as long as the rest of the sepals. Corolla 13–17 × 13–16 mm, as high as wide, flat in front view. Petals whitish to light violet; upper petals recurved, obovate, obtuse, 9–12 × 3.5–5.5 mm, 2–3 times as long as wide; lateral petals obovate, obtuse, 10–12 × 3.5–5 mm, 2.2–3 times as long as wide; spurred petal 9–12 × 4–6 mm excluding the spur, 1.6–2.5 times as long as wide; spur greenish, conical, blunt, straight or slightly curved downwards, 2.5–4 × 1.5–2.5 mm, 1.2–2 times as long as wide, 1.8–4 times as long as the sepal appendages. Style not papillose. Cleistogamous flowers 3–4 mm. Capsule ovoid, trigonous, obtuse, 6.5–9 mm, glabrous, explosive. Seeds ovoid, 1.6–1.9 × 0.7–1 mm, pale to dark brown; elaiosome small. – Mid-spring to late spring (chasmogamous flowers), summer (cleistogamous flowers).
2n=40 (S Sk). – [2n = 40]
Distribution. Nem–BNem. – S Sk Eskilstorp, found 1962, last seen 2003; Öl common, Gtl fairly common.
Temperate Eurasia, from E France, Germany and Estonia east to E Siberia and south to N Italy, Georgia and Uzbekistan. Most records of V. stagnina in W, C and E Siberia refer in fact to V. pumila (Eckstein et al. 2006).
Habitat. Seasonally damp, open, calcareous grassland, especially in mats of Carex hostiana, Molinia caerulea or Sesleria uliginosa in alvar depressions, but also in semi-shade in forest glades; more rarely among fruticose lichens on dry alvar gravel. In Sk Eskilstorp, V. pumila grew on ant-heaps in grazed seashore meadow.
Variation. Morphological variation is moderate and seems to be caused mainly by differing habitat conditions. The variation in height is notable; as a rule V. pumila is considered a small plant, but it may well produce aerial stems to 25 cm.
Taxonomy. . Viola canina has usually been considered a tetraploid based on x=10. However, since x=10 is itself a palaeotetraploid number the species is better considered an octoploid. Apparently it originated from hybridization between V. stagnina, or a similar taxon, and another taxon that no longer occurs in Europe (Moore & Harvey 1961).
Hybridization. Hybrids of Viola pumila are known with V. canina, V. elatior, V. reichenbachiana, V. riviniana, V. rupestris subsp. rupestris and V. stagnina.

17. Viola elatior Fr.       Map      ill.

Fries, Novit. fl. suec. alt.: 277 (1828), nom. cons. prop. – Viola montana L., Sp. pl.: 935 (1753). – Type: Linnaean Herbarum 1052.13 (LINN), sel. by Nikitin, Bot. Zhurn. 73: 1536 (1988).

D Stor Viol. F kaitaorvokki. Fa . I . storfiol. S storviol.

Literature. Aronsson 1999, Rosén et al. 1991, Sterner 1938, 1986.

Hemicryptophyte. Rhizomatous, caulescent perennial. Rhizome vertical, branching at or below the soil surface, covered with brown stipules; terminal leaf rosette absent. Aerial stems erect, to 50(–60)  cm, covered with short, white, downward-pointing hairs. Stem leaves up to 8; stipules of upper leaves oblong-elliptic, to 40 mm, 1.5–2.5 times as long as the petiole, green, hairy, entire or at the base with 1–2 coarse teeth; petiole of upper leaves to 2.5 cm, hairy; blade narrowly oblong to narrowly triangular, 35–60 × 12–22 mm, 2.5–3.5 times as long as wide, longer than the petiole, light green, covered with short, white hairs; margin entire or serrate with up to 12 forwards-pointing acute teeth; base cuneate, truncate or slightly cordate, not decurrent onto the petiole; apex acute.
Chasmogamous flowers scentless, from the upper part of the aerial stems. Pedicels hairy, to 5 cm, shorter than the subtending leaves; bracteoles subulate, in the upper half of the pedicel. Sepals lanceolate, acute, finely hairy at the margin, upper ones 5.5–10 × 1.2–2 mm, lateral ones 7–10 × 2–2.6 mm (in both cases excluding the appendage); appendage suborbicular to truncate, on upper sepals 1–2 × 0.8–1.8 mm, on lateral sepals 1.2–2.4 × 1.6–2.6 mm, all 0.16–0.32 times as long as the rest of the sepal. Corolla 20 × 17 mm, 1.1 times as high as wide, cup-shaped in front view. Petals light blue, white at the base; upper petals recurved, obovate, obtuse, 13–17 × 5–8 mm, 1.9–2.7 times as long as wide; lateral petals obovate, obtuse, 13–18 × 6–8 mm, 2–2.5 times as long as wide, with hyaline hairs at the throat; spurred petal sligtly concave, 13.5–16.5 × 7–9 mm excluding the spur, 1.6–2 times as long as wide; spur light green to yellow-green, cylindric, 3.5–5 × 2–3 mm, 1.3–2 times as long as wide, 1.7–4.5 times as long as the sepal appendages. Style papillose at the tip. Cleistogamous flowers 5–7 mm, produced above chasmogamous flowers or on side branches. Capsule ovoid, trigonous, acute, 6–8 mm, glabrous, explosive. Seeds ovoid, 1.4–1.6 × 0.65–0.8 mm, pale to light brown; elaiosome small. – Mid-spring to early summer (chasmogamous flowers), early summer to early autumn (cleistogamous flowers).
[2n=40]
Distribution. Nem. – N Ak Oslo 1947 (escaped from the Botanical Garden). S widespread in central Öl, known from 18 parishes, but strongly declining during the 20th century, mainly due to overgrowth; casual in Upl Bondkyrka 1931–32 (Rickomberga, with refuse from the botanic garden).
From C France, Germany and Estonia south to N Italy and the northern Balkans; east to W Siberia, Uzbekistan and NW China.
Habitat. In light shade or (more rarely) full sun on calcareous ground which is inundated in spring. – Shrubby grassland, woodland fringes, glades, damp meadows, karst alvar; rarely apophytic in ditches.
Biology. Management experiments have shown that V. elatior requires a good light supply; increased light stimulates germination as well as plant growth and the plentiful formation of both chasmogamous and cleistogamous flowers. It was also shown that full-grown plants did not regenerate when damaged. Therefore, mowing and grazing did increase germination rates but drastically lowered seed production (Rosén et al. 1991).
Taxonomy. Viola elatior has been reported to be an autotetraploid, based on n=10, because of the formation of quadrivalents in the meiosis (Clausen 1927). This is the only report of autopolyploidy within sect. Viola and is in need of verification.
The name Viola montana L. was lectotypified by Nikitin (1988; see also Nikitin 1995). Its type is identifiable as V. elatior, so V. montana is the earliest available name for that species. However, the name V. montana has been applied to a taxon of the V. canina group; further use of the name V. montana would therefore cause confusion, and it will be proposed for rejection (see Kirschner and Skalický 1989 and Eckmann et al. 2006).
Hybridization. Hybrids of Viola elatior are known with V. pumila, V. riviniana and V. stagnina..

18. Viola alba Besser      Map.      ill.

Besser, Prim. fl. Galiciae austriac. 1: 171 (1809). – Described from Poland.

D Hvid Viol. F hopeaorvokki. Fa . I . N hvitfiol. S silverviol.

Literature. Aronsson 1999, Ekstam et al. 1984, S. Johansson 1992, Sterner 1938, 1986.

Hemicryptophyte. Acaulescent, stoloniferous perennial usually without any red/blue colouring (anthocyanins lacking in all parts). Rhizome ± creeping, densely articulate, c. 3 mm thick, branched, with terminal leaf rosettes and lateral stolons. Rosette leaves several, hispid, wintering; stipules lanceolate to narrowly lanceolate, (7–)10–15 × 1.5–2 mm, acute, pale or sometimes greenish, remotely long-fimbriate (fimbriae c. 1 mm); petiole 6–15 cm; blade cordate, 5.5–7 × 3.5–5 cm; margins convex or straight towards the apex, crenate with 16–24 teeth; base cordate; apex acute or shortly acuminate. Stolons creeping, c. 1 mm thick and to 30 cm long, with 1.5–5 cm long internodes, ± rooting, in the second year with terminal and lateral leaf rosettes. Stolon leaves similar to the rosette leaves but usually smaller and blades often as wide as long or wider, triangular-reniform, with a shallowly cordate to almost truncate base.
Chasmogamous flowers heavily scented, from the leaf rosettes and from stolons. Pedicels of chasmogamous flowers with short hairs, 30–40 cm, ± exceeding the foliage at time of flowering; bracteoles c. 5 mm, in the middle third of the pedicel. Sepals oblong-lanceolate, obtuse, 5–6.5 × 1.7–2 mm (including the appendage); appendage c. 1 mm. Petals completely white, broad, obovate; upper petals 9–12 × 5–6 mm; lateral petals with or occasionally without hyaline hairs at the throat; spurred petal 12–15 × 5–7 mm including the spur; spur white or yellowish, 2.5–4 mm. Cleistogamous flowers 1–3 mm, on decumbent pedicel. Capsule globose, 5–8 mm, pilose, yellowish green, on decumbent pedicel, non-explosive. Seeds ellipsoid, c. 2 × 3 mm, ochre; elaiosome conspicuous, white. – Early spring (chasmogamous flowers); summer (cleistogamous flowers).
[2n=20]
Distribution. Nem. – S Öl southern Borgholm and adjacent Räpplinge, first observed in 1885. The Nordic area is isolated, the nearest occurrences being in southern Poland. Previous authors (e.g. Sterner 1938) regarded the species as indigenous, but in light of its occurrence only in the proximity of the garden of the castle in Borgholm, it seems more likely that it was originally introduced, perhaps as late as during the 19th century. – During the 20th century it has gradually become rarer due to overgrowth, urbanisation and the use of herbicides. In most of its localities vigorous hybrids with V. hirta and V. odorata are now more numerous than the pure species. – A record from S Vg Bollebygd (Westfeldt 1971) is due to misidentification.
S Europe north of the Alps; Turkey and the Caucasus (subsp. alba). Subsp. dehnhardtii (Ten.) W. Becker occurs in the Mediterranean region and subsp. cretica (Boiss. & Heldr.) Marcussen in Crete (Marcussen 2003).
Habitat. Moist, base-rich, moderately damp soil; requires sunny openings in the tree canopy and a not too dense ground vegetation cover. – Glades and sunny spots in deciduous woodland, coppices, along paths, gardens, and other disturbed ground. Hemerophilous.
Variation. The first Nordic collection of Viola alba (from 1885) included both anthocyan-pigmented and anthocyan-free specimens. This original variation seems to be lost, because all extant plants seem to be anthocyan-free. In Central Europe, the anthocyan-pigmented morph (with white or lilac flowers) has often been treated at the subspecies level, subsp. scotophylla (Jord.) Nyman, but this distinction seems exaggerated (Marcussen 2003).
The widely cultivated ‘Parma Violets’ with filled, scented flowers belong to Viola alba subsp. dehnhardtii (Malécot et al. 2007) but have erroneously been referred to V. odorata and V. suavis.
Hybridization. Hybrids of Viola alba are known with V. hirta and V. odorata.
Similar taxa. Viola alba is similar to V. collina and V. hirta in hairiness and sometimes in leaf shape, but it differs by producing long stolons and by lack of anthocyan (white flowers, pure green petioles and yellowish-green capsules). It is also somewhat similar to white-flowered morphs of V. odorata, from which it differs by having narrowly lanceolate, long-fimbriate stipules, acute leaves and much longer indumentum.

19. Viola odorata L.       Map      ill.

Linnaeus, Sp. pl.: 934 (1753). – Type: Burser Herbarium XI:1 (UPS) lectotype, sel. by Haesler, Mitt. Bot. Staatssamml. München 18: 294 (1982).

D Marts-Viol. F tuoksuorvokki. Fa . I ilmfjóla. N marsfiol. S luktviol.

Literature. Clausen 1931, Marcussen 1998, 2006, Marcussen & Borgen 2000, Marcussen et al. 2001, Rasmussen 1954.

Hemicryptophyte. Acaulescent, stoloniferous perennial. Rhizome ± creeping, densely articulate, 3–5 mm thick, branched, with terminal leaf rosettes and lateral stolons. Rosette leaves several, short-hairy; stipules ovate or broadly lanceolate, (7–)10–15 –(21) ´ 3–5 mm, acute, pale or sometimes greenish, densely fimbriate with fimbriae usually 0–1 mm but in some populations 1–2 mm; petiole (3–)5–17(–24) cm; blade ovate to orbicular, 4–8(–10) × (3–)4–7.5(–9) cm, broadest near the middle; margin convex, crenate with 20–26(–29) teeth; base cordate; apex obtuse. Stolons creeping, c. 2 mm thick and to 30 cm long, with 1–6 cm long internodes, rooting, in the second year with terminal and lateral leaf rosettes. Stolon leaves similar to the rosette leaves but smaller and blades sometimes wider than long, with a shallowly cordate to almost truncate base.
Chasmogamous flowers heavily scented, from the leaf rosettes and from stolons. Pedicels of chasmogamous flowers 4–5(–8) cm, exceeding the foliage at time of flowering or not; bracteoles 4–5.5 mm, in the middle third of the pedicel. Sepals ovate, obtuse, (3–)4.5–6 × 2.5–3.5 mm (including the appendage); appendage 1–2(–4) mm. Petals lilac, sometimes white or sordid pink, obovate; upper petals 7–8(–9) × 4–8 mm; lateral petals usually with hyaline hairs at the throat; spurred petal 15–21 × 5–8(–10) mm excluding the spur; spur variably violet, darker or lighter than the petal limbs, (2–)3–4.5 mm. Cleistogamous flowers 1–3 mm, on decumbent pedicel. Capsule globose, 8–12 mm, pilose and with purple stains, on decumbent pedicel, non-explosive. Seeds ellipsoid, c. 2 × 3 mm, ochre; elaiosome conspicuous, white. – Early spring, in some cultivars from autumn to early spring (chasmogamous flowers); summer (cleistogamous flowers).
2n=20 (S Sk). – [2n=20]
Distribution. Nem–BNem[–SBor]. Alt. N Bu Lier 200 m. – Cultivated since Medieval times for ornament and for the pleasant scent, and frequently escaped; in many areas naturalized, especially on calcareous soils; in lowland Sk and Öl since long found in natural habitats and sometimes held to be indigenous (Sterner 1938, 1986), elsewhere clearly anthropochorous. – D mostly common, but with lower frequency in northern NJy and in large parts of VJy. N scattered in the southeast from Øf Halden and Hvaler to Ak Oslo and Bu Modum, and further along the coast to VA Farsund; Ro Stavanger 1935, Ho Stord 1934; probably under-recorded, increasing at least in the south. S increasing in the whole area during the 20th century; common to fairly common north to northern Vg, Nrk, southeastern Vsm and Upl (but rarer in inland Hl, northern SmI and southern and central Vg); fairly rare in BhG, Dls, southwesternmost Vrm and in Gst; Dlr By 1988 (probably established), Hls Bollnäs and Söderhamn in the 1990’s, Harmånger 1887 (ballast), Mpd Sundsvall 1994 (street), Timrå 1880’s (ballast). F rare in the south, mainly in old manor parks and gardens, mainly west of the river Kymijoki (Russian border in the late 1700’s). – Also reported from N Ho Bergen and MR Kristiansund, but no specimens have been seen.
Europe W and S of the Alps east to Caucasus and N Iran; the Mediterranean islands; NW Africa; the Canary Islands and Madeira; scattered in C Asia (Alaj, Tian Shan). Frequently cultivated and naturalized throughout much of the temperate zone (C and E Europe; N America; E Asia; Australasia).
Habitat. Commonest as a relic of cultivation in parks and gardens; hedges, lawns, roadsides. Naturalized on warm, moderately dry, nutrient-rich and bas-rich soil. – Glades and forest edges, coppices, grassy slopes, sometimes in closed deciduous woodland (and then mainly vegetatively propagating).
Variation. Very heterogeneous in Norden due to multiple introductions (Marcussen et al. 2001). Nordic populations vary e.g. in leaf shape and hairiness, length of stipule fimbria, bracteole insertion, and corolla and spur size and colour. The Nordic forms correspond to the native forms found in SW Europe; Ponto-Caucasian plants deviate considerably and possibly represent a different subspecies (Marcussen 2006).
Hybridization. Hybrids of Viola odorata are known with V. alba, V. collina and V. hirta.
Similar taxa. Viola odorata is somewhat similar to V. alba (see this species).

20. Viola suavis M. Bieb.       Map      ill.

Marschall von Bieberstein, Fl. taur.-caucas. 3: 164 (1819). – Type: Ukraine, Mereffi, 1816 M. Bieberstein (LE), lectotype, sel. by Nikitin, Nov. Syst. Pl. Vasc. 31: 221 (1998).

D Smuk Viol. F samettiorvokki. Fa . I . N fagerfiol. S fagerviol.

Literature. Marcussen & Nordal 1998, Marcussen et al. 2001.

Hemicryptophyte. Acaulescent, stoloniferous perennial. Rhizome ± creeping, densely articulate, 4–5 mm thick, branched, with terminal leaf rosettes and lateral stolons. Rosette leaves numerous, short-hairy; stipules lanceolate to broadly lanceolate, 10–25 × 2.5–4.5 mm, acute, pale, long-fimbriate with fimbriae 1–3 mm; petiole (12–)15–25 cm; blade ovate, 8–13 × 6–9.5 cm, broadest in the lower third; margin convex, crenate with 29–36 teeth; base cordate; apex obtuse. Stolons creeping and sometimes underground, c. 2 mm thick and to 15 cm long, with 1–4 cm long internodes, rooting, in the second year with terminal and lateral leaf rosettes. Stolon leaves similar to the rosette leaves but somewhat smaller.
Chasmogamous flowers heavily scented, from the leaf rosettes and stolons. Pedicels of chasmogamous flowers glabrous, 5–8 cm, exceeding the foliage at time of flowering or not; bracteoles conspicuous, 9–11 mm, glandular-fimbriate, in the lower third of the pedicel. Sepals broadly lanceolate, obtuse, 8–11 × 3–3.5 mm (including the appendage); appendage 2–3 mm, appressed to the pedicel. Petals pale lilac or almost white, often with a shade of cyan, obovate and ± emarginate; upper petals c. 15 × 6.5–8 mm; lateral petals with sparse, rather long hyaline hairs at the throat; spurred petal 16–20.5 × 6–9 mm including the spur; spur darker lilac than the petal limbs, 2.5–3.5 mm. Cleistogamous flowers 1–3 mm, on decumbent pedicel. Capsule large and globose, 10–15 mm, densely short-pilose and with purple stains, on decumbent pedicel, non-explosive. Seeds ellipsoid, c. 2 × 3 mm, ochre; elaiosome conspicuous, white. – Early spring (chasmogamous flowers) and summer (cleistogamous flowers).
2n=c. 40 (N Te). – [2n=40]
Distribution. Nem. – Probably originally a garden escape but completely naturalized. N Te Kragerø, first recorded in 1890. – Also reported from S Upl (L. Jonsell et al. 1997), but the specimen is V. odorata.
From E Spain and C Italy north to S Poland and east to SW Russia, the Caucasus and N Iran; scattered in C Asia; NW Africa.
Habitat. Naturalized on moderately dry, nutrient-rich soil. – Open deciduous woodland, coppices, grassy slopes. Hemerophilous.
Variation. Nordic Viola suavis differs markedly from plants from the native range in southern Europe and the Caucasus (Marcussen & Nordal 1998). Plants from southern Europe usually have smaller, darker and more bluish flowers, usually more pure blue than those of e.g. V. hirta and V. odorata, with a light violet spur and rather short sepal appendages. Most populations have much smaller bracteoles (c. 5 mm) than the Nordic plants.
Taxonomy. Viola suavis probably originated through allopolyploidization from V. pyrenaica Ramond (non-stoloniferous, disjunct in SW Eurasian mountains) and an unknown stoloniferous species. It was divided into numerous taxa by Becker (1910a, 1918), but it is uncertain whether these warrant taxonomic recognition; see Marcussen & Nordal (1998) for a survey. The delimitation from V. sintenisii W. Becker (2n=20) in western and Central Asia is unclear.
Hybridization. No hybrids of Viola suavis have been reported from Te Kragerø, where it grows close to both V. hirta and V. odorata.

21. Viola collina Besser      Map      ill.

Besser, Cat. hort. Cremeneci: 151 (1816).  – Described from Ukraine (Kremenets).

D Bakke-Viol. F mäkiorvokki. Fa . I . N bakkefiol. S bergviol.

Literature. Aronsson 2005, Kosonen et al. 1996, Marcussen & Borgen 2000, Marcussen et al. 2001, Ryttäri & Kettunen 1997.

Hemicryptophyte. Acaulescent perennial; non-stoloniferous or with short stolons (internodes 3–10 mm). Rhizome ± creeping, 2–5 mm thick, branched, at apex densely articulate and with terminal leaf rosettes, usually not rooting. Leaves several, white-pilose; stipules lanceolate, (8–)10–16(–18) × 1.5–3 mm, acute, pale, with conspicuous fimbriae equalling half the width of the stipule; petiole 3–18 cm, distinctly purple-tinged in the lower third; blade cordate, 4–11 × 3.5–7.5 cm; margin convex and crenate with 21–27(–29) teeth; base cordate; apex somewhat acuminate.
Chasmogamous flowers scented, from the leaf rosettes. Pedicels of chasmogamous flowers almost glabrous, (2.5–)4–5.5(–8) cm, usually exceeding the foliage at time of flowering; bracteoles 4–6 mm, in the middle third of the pedicel. Sepals lanceolate to broadly lanceolate, obtuse, (5–)6–9 × (2–)2.5–3(–4) mm (including the appendage); appendage 1–2 mm. Petals pale lilac (rarely white), obovate; upper petals 8–14 × (3–)4–6 mm; lateral petals with hyaline hairs at the throat; spurred petal (11–)13–16(–18) mm long including the spur; spur white, (2–)2.5–4 mm. Cleistogamous flowers 1–3 mm, on decumbent pedicel. Capsule globose, 8–10 mm, pilose and with purple stains, on decumbent pedicel, non-explosive. Seeds elliptical, c. 2 × 3 mm, ochre to sepia; elaiosome conspicuous, white. – Early spring (chasmogamous flowers) and summer (cleistogamous flowers).
[2n=20]
Distribution. BNem–MBor. Continental. Alt. N Op 950 m. – N fairly common in the southeast, more or less continuously distributed from Øf Moss and Vf Holmestrand north to He Løten (absent from Østerdalen valley), Op Lesja and Vang and Bu Hol; Te Skien and Porsgrunn, SF Lærdal and Luster; an isolated area in Trøndelag from ST Melhus to NT Inderøy and Bjugn. S fairly common in Mpd along the coast and in the lower river valleys of Ljungan and Indalsälven; Dlr Sundborn (2 localities) and Svärdsjö (4 localities), Hls Gnarp (Grängsjöberget) and Ång Viksjö (Billberget). F St Vammala (found in four nearby places) and EH Sysmä. – A specimen from S Bl Lyckeby 1910 is possibly mislabelled.
Outside Norden from the SW Alps and the Baltic states throughout Siberia south to the Alaj mountains and east to the Amur region and Sakhalin; much of China, Korea; N Japan.
Habitat. Dry places in sun or light shade, on shallow and somewhat unstable mineral soil (pH 6.0–7.5), often in south-facing slopes; calcicole. – Margins of deciduous and coniferous woodland, coppices, Rosa and Berberis thickets, sedimentary rock ledges and crevices, gravelly scree and talus, more rarely (and probably not persistent) in shady eutrophic forest. Apophytic along paths and railway embankments.
Variation. Nordic Viola collina is fairly homogeneous, and the same can be said for the species as a whole. Plants from Central Europe differ only very slightly in leaf shape and overall pigmentation, while plants from East Asia differ somewhat more in the shape of the corolla.
Hybridization. Hybrids of Viola collina are known with V. hirta and V. odorata.
Similar taxa. Viola collina is similar to V. hirta (22) but differs in, e.g., having bracteoles inserted in the middle part of the pedicel, white spur, and petioles distinctly pigmented in the lower third. – Several Central European Floras have reported that V. collina differs from V. hirta in having a short spur that does not exceed the sepal appendages. There is, however, no noticeable difference between the two species in this character, neither in Nordic material nor in material from Central Europe and elsewhere. – See also V. selkirkii (6).

22. Viola hirta L.       Map      ill.

Linnaeus, Sp. pl.: 934 (1753). – Type: Brunfels, Herbarum Vivae Eicones 1: 137, f. 3, lower right, ill. design. ”Viola” (1530) lectotype, sel. by Haesler, Mitt. Bot. Staatssamml. München 18: 292 (1982).

D Håret Viol. F karvaorvokki. Fa . I . N lodnefiol. S buskviol.

Literature. Clausen 1931, Marcussen 1998, Marcussen et al. 2001, Rasmussen 1954.

Hemicryptophyte. Acaulescent, non-stoloniferous perennial. Rhizome ± vertical, 3–5 mm thick, branched, with terminal leaf rosettes, densely articulate (lateral branches occasionally with 5–10 mm long internodes). Leaves several, pilose; stipules lanceolate, (6–)10–17(–21) × 2–3.5 mm, acute and pale (or sometimes obtuse and greenish), with distant, inconspicuous fimbriae less than 1 mm; petiole (4–)8–28(–36) cm; blade triangular-cordate, 5–11 × 3.5–7.5(–9) cm; margin usually straight, crenate with 20–33(–37) teeth; base shallowly cordate to almost truncate; apex obtuse.
Chasmogamous flowers scentless, from the leaf rosettes. Pedicels of chasmogamous flowers somewhat hairy, 3–10 cm, exceeding the foliage at time of flowering or not; bracteoles 4–5 mm, in the lower third of the pedicel. Sepals ovate, obtuse, (4–)5.5–7 × 2.5–3.5(–4.5) mm (including the appendage); appendage 0.5–1 mm. Petals lilac (rarely white), obovate and ± emarginate; upper petals 8–18 × 6–9 mm; lateral petals with or occasionally without hyaline hairs at the throat; spurred petal 14–20(–22) × 5–9 mm including the spur; spur purplish violet, 2–4(–5) mm. Cleistogamous flowers 1–3 mm, on decumbent pedicel. Capsule globose, 8–10 mm, pilose and with purple stains, on decumbent pedicel, non-explosive. Seeds elliptical, c. 2 × 3 mm, ochre to sepia; elaiosome conspicuous, white. – Spring (chasmogamous flowers) and summer (cleistogamous flowers).
[2n=20]
Distribution. Nem–BNem[–SBor]. – D scattered to rare in NJy (Limfjorden area), ØJy (especially the Århus area) and FyL, fairly common in western LFM, Sjæ and Brn; SJy Sundsmark c. 1880.. N four separate areas in the southeast: rare in the middle part of Oslofjorden (Øf Moss, Bu Hurum, Vf Våle and Borre); Ak Oslo, apparently increasing; Bu Hole close to Tyrifjorden; Te Kragerø (introduced, the same locality as V. suavis). S very common in Öl; fairly common in lowland Sk, coastal Bl, and from Ög north to southeastern Vsm and southern and central Upl; scattered in Klm (in the south only at the coast), northernmost SmI, in Gtl and in Vg (more common in the central limestone area); Hl Rolfstorp, Vessige and Östra Karup, BhG Göteborg and Kville, Dlr Falun 1940’s and Hls Söderhamn (Lugnsjön) 1988 (in both cases from cultivation). F A Jomala 1882 (pupil specimen); a relic of cultivation or spread in old garden and park areas in V Karjalohja, Sauvo (two places), U Helsinki (several places) and its neighbourhood, St Eura (Kauttua manor park), EH Hämeenlinna (Aulanko park).
From NE Spain and the British Isles east to the Baikal area; the Caucasus; Tian Shan and Altai.
Habitat. Sunny to half-shady, mostly south-exposed sites on dry to moderately dry, base-rich but moderately nutrient-rich, clayey soil; calciphilous. – Grazed, open deciduous woodland, groves and coppices, forest edges, Rosa and Prunus spinosa thickets, at the base of rocks in dry meadows, alvar (especially in karst), more rarely in the upper flood-zone of lakes and on shell deposits on seashores. Somewhat hemerophilous: paths and roadsides, more rarely lawns and hedges in parks.
Variation. Variable throughout its range, also in Norden, especially in internode length, relative width of the leaf-blade, shape of the base of the leaf-blade (cordate or truncate), petal colour and presence of hyaline hairs at the base of the lateral petals. Combinations of these traits are often genetically fixed locally; e.g. the populations in the four separate areas in southeastern N are morphologically distinct (Marcussen et al. 2001).
Hybridization. Hybrids of Viola hirta are known with V. alba, V. collina and V. odorata.
Similar taxa. Viola hirta is similar to V. collina (see that species).

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Rare casuals

Viola lanceolata L. 1753. F amerikanorvokki. S lansettviol. – Acaulescent and stoloniferous, glabrous perennial, distinguished from all other species found in Norden by its lanceolate to spathulate leaf-blades 2–5 × 0.5–1.2 cm. Petals cream white, the spurred one conspicuously veined with lilac. – [2n=24]
F St Köyliö 1950, brought in with Vaccinium macrocarpum plants from USA (Massachusetts). – Map (not in the book). TM
Viola lutea Huds. 1762. S gulviol. – Similar to Viola ×wittrockiana, but perennial, and stipules with linear to narrowly lanceolate, entire apical lobe and elongated, narrow, forwards-pointing lateral lobes. Flowers yellow (in the Nordic specimen; variants with violet or parti-coloured flowers also occur). – [2n=48, 50, 52]
Sometimes cultivated for ornament; escaped in F U Helsinki (Pasila dump) 1961. – A record from S Upl (L. Jonsell et al. 1997) was based on a yellow-flowered specimen of V. tricolor. – Map (not in the book).
Native to Europe; one of the parents of the pansies (Viola ×wittrockiana)     TK
Viola ×williamsii Wittr. 1897 (V. cornuta × V. ×wittrockiana). F tarhasarviorvokki. S bukettviol. – V. ×williamsii differs from V. cornuta in having wider, slightly overlapping petals, the lateral ones directed outwards or upwards, and more deeply dentate to laciniate stipules with the apical lobe clearly narrowed towards the base. It differs from V. ×wittrockiana in at least one of the following characters: perennial habit, scented flowers and a longer spur.
Sometimes escaped. N Bu Drammen 1999, Lier 1995, AA Bygland 2001, Lillesand 2002, Ho Samnanger 1995. S SmI Dädesjö 1991, Gtl several records (Johansson & Larsson 1997), Upl Lidingö 1932, Hls Hudiksvall 1949, 1956. – Many unconfirmed records of V. cornuta are probably based on this hybrid. – Published from S Upl (L. Jonsell et al. 1997) but the specimen is V. ×wittrockiana. – Map (not in the book).
This group of cultivars originated in the 1860’s in the British Isles by hybridization between V. cornuta and V. ×wittrockiana (Wittrock 1895).                              TK

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Hybrids

The hybrid Viola elatior × reichenbachiana has been described (Becker 1914) but the plants were later redetermined to V. elatior × riviniana (Becker 1925b).

A report of V. odorata × suavis (Lid & Lid 2005) was based on V. suavis.

V. palustris × uliginosa has been reported from D Brn and S Sk, probably incorrectly

V. rupestris subsp. rupestris × stagnina was published by Holmgren (1942) from S Bl Kristianopel (Brömsebro), but no voucher has been found.

V. rupestris × uliginosa was published by Becker (1927) from S Öl (Karlevi; see under V. riviniana × uliginosa).

Viola alba × hirta. – Vigorous. Differences from V. alba: stolons much shorter; stipules wider, lanceolate. Differences from V. hirta: stolons present; stipules fimbriate. Somewhat similar to V. alba × odorata but leaves narrower, hairs longer and stolons shorter. Flowers white with a violet border and violet streaks. Somewhat fertile; capsules with 1–2 seeds.
Fairly common in S Öl Borgholm and Räpplinge within the small area of V. alba (Johansson 1992). - Map (not in the book). TM
Viola alba × odorata. – Vigorous, forming clones by very long stolons (30–40 cm or more). Differences from V. alba: leaves wider; stipules lanceolate (not linear); hairs shorter. Differences from  V. odorata: leaves narrower; stipules lanceolate (not ovate) and distinctly fimbriate. Flowers white with a violet border and violet streaks. – Sterile or with occasional 1-seeded capsules.
Fairly common in S Öl Borgholm and Räpplinge within the small area of V. alba (Johansson 1992).- Map (not in the book). TM
Viola arvensis × cornuta. – Differences from V. arvensis: stipules large, coarsely dentate (not laciniate); spur long; petals violet. Differences from V. cornuta: stipules with enlarged apex, deeply dentate; petals small.
S Nrk Örebro (Adolfsberg) 1927. - Map (not in the book). TK
Viola arvensis × tricolor. – Easily raised in experiments, and viable. Intermediate in corolla size and colour, shape of stylar flap and secondary pollen presentation mechanism. Pollen grains with 4 and 5 pores in about equal numbers. – Fairly fertile, with c. 70% good pollen and with good seed-set, giving viable and fertile offspring (Clausen 1921, 1922, 1926). Nevertheless, hybrid stands usually sooner or later disappear and there is no evidence of large-scale introgression. – Lit.: Clausen (1922). – 2n=30 (D Sjæ, S Sk).
Probably common wherever the parents meet. D cytologically confirmed from Sjæ Vorgård, Terndrup, Hadsund (Clausen 1921); frequently reported from NJy, VJy, SJy and western ØJy, elsewhere more rarely. N scattered reports in the lowlands from Øf along the coast to ST, probably under-reported.. S reported from most mainland provinces north to Dlr and Gst (not Dls, Vrm) and from Mpd, Ång and Vb; most specimens have, however, not been critically examined. F reported from, at least, V, U, PK, Kn and OP, but the material has not been critically examined. – The hybrid with V. tricolor subsp. curtisii is known from S Gtl Fårö. - Map (not in the book). TK
Viola arvensis × wittrockiana. – Differences from V. arvensis: flowers larger; stipules very wide at the base and with short lateral lobes. Differences from V. ×wittrockiana and V. tricolor × wittrockiana: flowers smaller and usually paler. Herbarium specimens are difficult to evaluate due to the large variation in V. ×wittrockiana, but field observations may be conclusive.
Reported from S  Klm (11 localities), SmI (3 localities), F EH Kuhmoinen 1953, Ks Taivalkoski. – A report from S Sk (Tyler et al. 2007) is due to misidentification. - Map (not in the book). TK

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Viola canina × mirabilis. – Similar to V. mirabilis × riviniana but richly branched from the base and without a terminal leaf rosette; upper stem leaves more elongated and with wider and (almost) entire stipules. – Not obtained in experiments (Valentine 1962), and there are no other records, but not an unlikely hybrid.
S Jmt Brunflo (Ope and Opetand; Lange 1938). - Map (not in the book). TK
Viola canina × pumila. – Easily raised in experiments, and vigorous (Valentine 1962); locally common in C Europe (Becker 1917). Intermediate between the parents in stipule size and shape of  the leaf-blade; differs from V. canina × stagnina in having longer stipules (at least on the upper leaves) and at least some leaf-blades with broadly cuneate base. See also V. pumila × stagnina.
Apparently common in S Öl and Gtl, but the case has not been closely investigated. - Map (not in the book). TK
Viola canina × reichenbachiana. – Easily raised in experiments, and vigorous (Valentine 1962). Closely similar to V. canina × riviniana but with more lilac flowers; difficult to distinguish from the mentioned hybrid in herbarium material. – Infertile, but less so than V. canina × riviniana (Valentine 1975).
D recorded from NJy, VJy, SJy, LFM, Sjæ and Brn. S plausible specimens seen from Sk, Bl, Öl, Gtl and Vg. - Map (not in the book). TK
Viola canina × riviniana. – Easily raised in experiments (Valentine 1962). Extremely vigorous (Schmidt 1961, Schöfer 1954) with finally strongly elongated stems; often forming wide stands by profuse branching from the rhizome. The flowers are sometimes variegated in white and lilac (fairly frequently seen at least in S Sk, Klm and SmI), indicating some kind of developmental disturbance. Differences from V. canina: stipules fimbriate; leaf-blades more roundish, with more deeply cordate base. Differences from V. riviniana: strongly branched from the base, without a true rhizome and without a terminal rosette. – Almost completely seed sterile; there is no evidence for backcrossing or introgression.
Widespread and common (in large areas by far the commonest Viola hybrid), often also in the absence of one of the parents. D known from all provinces. N northwards to Tr Balsfjord and Karlsøy. S reported from all provinces except from ÅsL, LyL, PL, LL and TL. F reported from all provinces except KiL, SoL, EnL and InL. - Map (not in the book). TM, TK
Viola canina × rupestris subsp. relicta. – Differences from V. canina: stems, petioles and peduncles finely hairy. Differences from V. rupestris subsp. relicta: flowers larger (lower petal to 12 × 10 mm); terminal leaf rosette absent; shoots spreading.
Material seen from *** and EnL Enontekiö (Saana); also reported from N Tr and VFi (Lid & Lid 2005), S LL Tjårgesvare. - Map (not in the book). BJ
Viola canina × rupestris subsp. rupestris. – Vigorous. Differences from V. canina: usually with hairs of irregular length and density along stems, petioles and peduncles; stipules wider, with narrowly triangular teeth. Differences from V. rupestris: length and distribution of hairs more irregular; profusely  branched from the base (usually without a terminal leaf rosette); leaves elongated. Differences from V. canina × riviniana: usually puberulent; stipules dentate (not fimbriate). – Largely sterile, but occasional viable seeds are formed (Schmidt 1961).
Probably not uncommon where the species grow together, occasionally in the absence of one of the parents. N ***, material seen from Sk Vitaby, Öl Vickleby, Gtl Boge and Othem, Klm Döderhult, Vg ***, Ög ***, Vrm Färnebo (Långbanshyttan), Nrk Ekeby, Upl Hållnäs (verified by isozyme pattern), Uppsala, Dlr Boda, Norrbärke, Hls Ljusdal, Mpd Alnön, Liden, Jmt Brunflo, Frösön; recorded from several more places in these provinces and also from Bl, SmI, Vsm, Ång and Hrj. at least U, St, EH, ES, PS and PK..  - Map (not in the book). BJ
Viola canina × stagnina. – Easily raised in experiments (Valentine 1962). Very vigorous, often taller than either parent and sometimes forming extensive stands by vegetative reproduction. Differs from V. canina in having more elongated leaves and larger stipules, from V. stagnina in having deeper blue flowers with slightly longer, whitish spur. – Highly seed sterile. – Lit.: Røren (1993), Røren et al. (1994). – 2n=30 (N Ak 3, Bu 4, He).
Common where the parents meet and also in places where V. stagnina is not (nowadays) found. D reported from FyL, Sjæ and Brn. N Øf Sarpsborg and Rygge, Ak Fet and Skedsmo, He Nord-Odal, Kongsvinger, Stange and Hamar, Bu Lier, Modum and Ringerike. S known from all provinces north to Dlr and Gst (except Hl, BhG and Dls). F A Lemland and Sottunga, V Lohja and St Kokemäki. - Map (not in the book). TM, TK
Viola canina × uliginosa.– A vigorous hybrid, most similar to V. canina, but aerial stems short (or absent) and flowers conspicuously long-pedicellate, stipules almost entire, leaves glossy, and sepals more obtuse. Differences from V. uliginosa: flowers on aerial stems; stipules ± dentate; sepals acute; cleistogamous flowers present. Differences from V. riviniana × uliginosa: leaves more elongated (length/width ratio 1.4–1.7); terminal leaf rosette absent. – Pollen and seed sterile. – Lit.: Kupffer (1903; also ill.), Erikson (1904).
S Bl Kristianopel (Brömsebro), Öl Vickleby (Karlevi), Klm Hossmo, Madesjö and Sankt Sigfrid, and Gst Österfärnebo (Gysinge). F A Kökar, ES Valkeala. - Map (not in the book). TM, TK
Viola collina × hirta. – Easily formed and vigorous. Most similar to V. hirta, but with bracteoles in the middle third of the pedicel; differs from V. collina in having larger, scentless flowers. Somewhat fertile; cleistogamous capsules with 1–2 seeds. A single introgressed allele from V. collina into V. hirta has been documented in one individual in Ak Oslo (Lindøya), otherwise only primary hybrids were found in a study in southeastern N (Marcussen et al. 2001).
N fairly common where the parents meet; confirmed by isozyme studies from Ak Oslo (several localities) and Bu Hole (three localities). - Map (not in the book). TM
Viola collina × odorata. – Vigorous; stoloniferous like V. odorata. Differs from V. collina in having stolons, wider stipules and larger flowers, from V. odorata in having longer leaves and narrower stipules. Somewhat fertile; cleistogamous capsules with 1–2 seeds.
N fairly common where the parents meet; known from Øf Moss, Ak Oslo (in 4 localities confirmed by isozyme studies, Marcussen et al. 2001) and Bu Drammen and Modum. - Map (not in the book). TM

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Viola elatior × pumila. – Differences from V. elatior: hairiness more sparse; darker green; stipules narrower; leaf-blades partly with broadly cuneate base. Differences from V. pumila: larger and ± puberulent. Differences from V. elatior × stagnina: leaf-blades narrower, at least some with cuneate base.
S Öl (known from 16 localities within 9 parishes; Sterner 1986). - Map (not in the book). TK
Viola elatior × riviniana. – A very distinctive plant. Differences from V. elatior: stipules smaller, distinctly fimbriate; leaf-blades ovate with cordate base. Differences from V. riviniana: stouter and more erect; leaves much longer; stems and leaves ± hairy; terminal leaf rosette absent; stipules larger, ± dentate; spur short. – Sterile. – Lit.: Becker (1914, 1925b).
S Öl (known from 6 localities within 4 parishes; Sterner 1986). - Map (not in the book). TK
Viola elatior × stagnina. – Differences from V. elatior: more sparsely hairy; stipules shorter; flowers paler. Differences from V. stagnina: ± puberulent; stipules longer; flowers violet. Differences from V. elatior × pumila: leaf-blades somewhat wider, with truncate to slightly emarginate base.
S Öl (known from 14 localities within 8 parishes; Sterner 1986).- Map (not in the book). TK
Viola epipsila × palustris (V. ×ruprechtiana Borbás 1891). F kosteikko-orvokki. – In general intermediate between the parents; difficult to identify, especially on herbarium material, because of morphological overlap with both parents. – Best characterized by failure to set capsules and seeds (the fertility is strongly reduced, at least in southern N). – Lit.: Brandrud (1989; also ill.), Brandrud & Borgen (1987). – 2n=36 (D Sjæ, N Ak 6, Bu, Op, Vf).
Probably occurring throughout the area of V. epipsila, cytologically confirmed from D Sjæ Jonstrup Vang and from N Ak, Bu, Op, Vf. Plausible specimens have been seen from N the southeastern part, Trøndelag and the northernmost parts, S all mainland provinces except Bl, Klm, Hl, BhG, Dls and Srm and F all provinces (common). - Map (not in the book). TM

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Viola hirta × odorata. – Easily formed and vigorous. Differs from V. hirta in at least one of the following features: stolons present; stipules and leaf-blades shorter and wider; flowers slightly scented. Differs from V. odorata in at least one of the following features: stolons short or absent; stipules and leaves elongated; flowers scentless. – Partially fertile, the fertility depending on the parental populations involved; capsules from cleistogamous flowers with 1–4 seeds, but often more seeds are found in capsules from chasmogamous flowers. –  Very variable. However, in a study in southeastern N (Marcussen et al. 2001) only primary hybrids were recorded and the variation was entirely due to plasticity and differences in the parental populations, especially in V. odorata. Introgression is probably rare in Norden.
To be expected wherever the species meet. D FyL, Sjæ, LFM, Brn. N Øf Moss, Ak Oslo. S Sk, Bl, Öl, Ög, Srm, Upl and Vsm. – Also reported from D NJy and S Gtl, SmI and Vg, but specimens have not been seen. Records from F A Jomala 1941 and U Helsinki 1949 were based on misdetermined V. odorata. - Map (not in the book). TM
Viola mirabilis × reichenbachiana. - Despite many efforts not obtained in experiments (Valentine 1962), but perhaps involved in the origin of V. pseudomirabilis Coste from S Europe. Closely similar to V. mirabilis × riviniana but said to have slightly more elongated leaves and shorter sepal appendages. - Sterile.
Rare, only in S Öl held to be less uncommon than V. mirabilis × riviniana. Reported from D Sjæ Allindelille, S Sk c. 30 localities, Öl 13 localities, Gtl Hejnum (Bjers), Klm Döderhult and Oskarshamn and Vg Medelplana (Munkängen). The specimens have not been critically checked and in view of the failure to synthesize the hybrid some records may be due to misidentification. - Map (not in the book). TM, TK
Viola mirabilis × riviniana. – Easily raised in experiments (Valentine 1962). Vigorous, in habit resembling V. mirabilis but with 3–5 stem leaves, fimbriate stipules and chasmogamous flowers from the aerial stems (rare in V. mirabilis); petals usually a darker lilac; cleistogamous flowers with longer pedicels. Differences from V. riviniana: rhizome with scale-like leaves below the rosette; stipules with shorter fringes; leaf-blades a lighter green. – Sterile.
Subglabrous plants from F EH Tampere, fully fertile but lacking the abaxial line of hairs typical of V. mirabilis, have been interpreted as backcrossed hybrids and assigned to the S European V. pseudomirabilis Coste (Harmaja 2003b); however, in other characters these plants fall within the normal range of variation of V. mirabilis, and they are probably just aberrant forms of the species.
Fairly rare. D Sjæ Allindelille, Basnæs and Rygårds Dyrehave, FyL Odense 1873. N single localities north to ST Trondheim, NT Snåsa (somewhat doubtful) and NNo Beiarn. S known from all provinces north to Jmt and Ång except Bl, Vsm, Hls and Hrj, but only in Sk, Öl and Gtl more frequent. F reported at least from A Finström, Jomala and Mariehamn, EH Kuhmoinen and PH Multia, but the specimens have not been checked. - Map (not in the book). TK
Viola mirabilis × rupestris subsp. rupestris. – Differences from V. mirabilis: stem with short, straight, downwards-pointing hairs all around; rosette leaves smaller (to 4.5 × 5 cm), more acute, with larger length/widh ratio; stipules narrower, with a few short teeth; flowers smaller, to 18 mm high in front view. Differences from V. rupestris: stem with longer hairs (to 0.3 mm); stem leaves more numerous; stipules wider (to 3.5 mm wide) with up to 6 pairs of short, acute teeth. The hybrids of V. mirabilis with V. riviniana and V. reichenbachiana differ in being ± glabrous and in the narrower stipules. – Seed sterile.
Rare; specimens seen from N ***, ***. – Vouchers not checked for the records from N Ak (Bærum), He (Eidskog 1991 & Elverum 1991), NT (Levanger 1910), Gtl Othem, Vrm Färnebo (Långbanshyttan), Nrk Ekeby, Dlr Boda, Mpd Alnö and Jmt Brunflo and Frösön, F St Vammala and Nokia and EH Korpilahti, Lammi and Luhanka. - Map (not in the book). BJ

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Viola pumila × reichenbachiana. – Closely similar to V. pumila × riviniana, but usually slenderer, and the leaf-blades have slightly concave sides (not straight or slightly convex); flowers slightly more reddish lilac.
S Öl Hulterstad (Gösslunda) and possibly Böda; Gtl Dalhem, Etelhem, Halla, Hörsne and Stånga. - Map (not in the book). TK
Viola pumila × riviniana. Differences from V. pumila: stipules much smaller; leaf-blades shorter, the lower ones with truncate or slightly cordate base. Differences from V. riviniana: branched from below (without a true rhizome); leaf-blades more elongated (almost triangular, with almost straight sides), the upper ones with truncate or broadly cuneate base. Differences from V. canina × riviniana: stipules usually larger; leaf-blades more elongated (almost triangular, with almost straight sides).
Reported from S Öl (6 localities in 4 parishes, Sterner 1986) and Gtl (4 localities in 3 parishes; Johansson 1897). - Map (not in the book). TK
Viola pumila × rupestris subsp. rupestris. – A very distinct plant. Differences from V. pumila: stems, petioles and peduncles often with fine papilla-like hairs; leaf-blades broader; all stipules shorter than the petiole. Differences from V. rupestris: terminal leaf rosette absent; leaf-blades much narrower; stipules longer in relation to the petiole. Differences from V. canina × rupestris: blade of upper stem leaves more elongated and with truncate to slightly cuneate base.
Specimens seen from S Öl Borgholm, Hulterstad and Vickleby and Gtl Hörsne; published from a few more places (Sterner 1986, Johansson 1897) but apparently rare. - Map (not in the book). BJ
Viola pumila × stagnina. – Differences from V. pumila: stipules narrower, almost entire; sepals shorter; flowers with shorter spurs. Differences from V. stagnina: leaf-blades weakly dentate with a ± cuneate leaf base. Differences from V. canina × pumila: slenderer; flowers paler blue; leaf-blades less obtuse. – Sterile. – Lit.: Becker (1910a).
Regarded as fairly common in S Öl (Sterner 1986) and also reported from Gtl (5 localities in 5 parishes; Johansson 1897), but no close study has been made. - Map (not in the book). TK

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Viola reichenbachiana × riviniana. – Easily raised in experiments, and vigorous (Valentine 1962). Primary hybrids are most similar to V. riviniana in petal width and length of sepal appendages, but they have a rather dark spur like V. reichenbachiana. Very difficult to identify unless compared with the parents in the field. – Somewhat fertile; cleistogamous capsules occasionally with 1–2 seeds. Backcrosses with the parents are easily made, but later-generation hybrids rapidly segregate back to the ploidy levels of either parent (Valentine 1950, Schöfer 1954). Introgression is difficult to substantiate but is likely to occur in C Europe (Neuffer et al. 1999) as well as in Norden (Marcussen et al. 2003).
Likely to be present wherever the species meet. D reported at least from NJy, VJy, SJy, Sjæ and Brn. S plausible specimens seen from Sk, Bl, Öl, Gtl, Klm, Hl, Vg, Srm and Upl. – Reports from F A doubtful (Kurtto & Lahti 1987); vouchers not checked. - Map (not in the book). TM, TK
Viola reichenbachiana × rupestris subsp. rupestris. – Difficult to raise in experiments (Valentine 1962). Closely similar to V. riviniana × rupestris but with slightly narrower leaves and narrower lateral petals. – Sterile. – Lit.: Becker (1910a).
Probably not distinguishable with certainty from V. riviniana × rupestris without chromosome counting or isozyme analysis; held to be rare, plausible specimens seen from S Öl Borgholm, Gtl Lojsta, Roma, Ög Omberg. - Map (not in the book). BJ
Viola reichenbachiana × stagnina. – Differences from V. reichenbachiana: leaf-blades longer, with almost straight sides or slightly concave sides. Differences from V. stagnina: leaf-blades with distinctly cordate base. Closely similar to V. riviniana × stagnina and perhaps not distinguishable on herbarium specimens. – No viable hybrids were obtained in experiments (Valentine 1962). Closely similar to V. riviniana × stagnina and perhaps not distinguishable on herbarium specimens.
Plausible specimens have been seen from S Gtl Dalhem. - Map (not in the book). TK
Viola reichenbachiana × uliginosa. – Said to be closely similar to V. riviniana × uliginosa but slenderer, with more elongated upper leaves and shorter sepal appendages. – Lit.: Becker (1925b).
Alleged specimens seen from D Brn Vallensgårds Mose 1950 and S Öl Vickleby (Karlevi) 1923–26. - Map (not in the book). TK
Viola riviniana × rupestris subsp. relicta. – Morphologically similar to V. riviniana × rupestris subsp. rupestris. Abundant and apparently easily formed in the narrow locality of V. rupestris ssp. relicta in N MR. The parents grow in close proximity but the hybrid does not enter the drier karst crevices where V. rupestris ssp. relicta grows (Nordal et al. 2005).
N MR Fræna (Trollkyrkja caves). – Also reported from N Tr Kvænangen (Lid & Lid 2005), but no specimens have been found. - Map (not in the book). TM
Viola riviniana × rupestris subsp. rupestris. – Easily raised in experiments (Valentine 1962). Vigorous, sometimes forming large clones by vegetative growth. Differences from V. riviniana: usually with hairs of irregular length, (0.1–)0.2–03(–0.5) mm, and density along stems and petioles (V. riviniana is sometimes hairy but is seed fertile); stipules slightly wider. Differences from V. rupestris: stipules narrower, more pointed and with more distinct fringes; flowers larger, in front view 15–25 × 15–25 mm, and with longer sepals (usually 5–5.5 mm). – Completely seed sterile. – Lit.: Becker (1910a), Schmidt (1961).
Not rare where the species grow together. N ***. S vouchers seen from Öl, Gtl, Klm, Vg, Ög, Dls, Vrm, Nrk, Srm, Upl, Vsm, Dlr, Hls, Mpd and Jmt; unconfirmed reports from Sk (Tyler et al. 2007, only misidentified vouchers seen), Hl (Nilsson 1966, no voucher) and Ång.. F vouchers seen from A, V, St and EH (also reported from U). - Map (not in the book). BJ
Viola riviniana × stagnina. – Raised in experiments but moderately vigorous (Valentine 1962). Plants from N Bu Lier were vigourous in culture for several years. Differences from V. riviniana: leaf-blades longer, with almost straight sides. Differences from V. stagnina: leaf-blades with distincly cordate base. Differences from V. canina × stagnina: leaf-blades shorter, with distinctly cordate base; stipules fimbriate. - Sterile.
Apparently very rare. N Bu Lier. Plausible specimens seen from S Öl Räpplinge, Klm Döderhult and Upl Harbo. – Also reported from S Vg Hassle (Bertilsson et al. 2002), but the specimen is not convincing. - Map (not in the book). TM, TK
Viola riviniana × uliginosa. – Differences from V. riviniana: aerial stems short and flowers conspicuously long-pedicellate, stipules almost entire, leaves glossy, and sepals more obtuse. Differences from V. uliginosa: leaf-blades c. as long as wide; flowers on aerial stems; stipules fimbriate; sepals acute. Differences from V. canina × uliginosa: leaves shorter and wider (length/width ratio 1–1.3); stipules fimbriate; terminal leaf rosette present. – Pollen and seed sterile. – Lit.: Kupffer (1903; also ill.).
Some of the collections of V. uliginosa hybrids from S Öl Vickleby are hairy in patches (especially on the pedicels) and smaller, and was interpreted by Becker (1927) as V. rupestris × uliginosa; however, it is possible that the other parent was not V. rupestris but a hairy morph of V. riviniana.
D Brn Vallensgård Mose at least to 1969; S Sk Allerum 1940–62, Bl Torhamn (Brunnsvik), Öl Vickleby (Karlevi) 1916–51, Upl Jumkil 1936 and Söderfors 1884. – Also published from S Klm (Erikson 1904) but the specimens were later referred to V. canina × uliginosa. - Map (not in the book). TK

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Viola stagnina × uliginosa. – Similar to V. canina × uliginosa slenderer, with longer and narrower leaf-blades (length/width ratio 1.9–2.3), almost entire stipules, and pale blue flowers. – Lit.: Becker (1925b).
D Brn Vallensgård Mose, several finds since 1909. S Öl Vickleby (Karlevi 1919–24). - Map (not in the book). TK
Viola tricolor × wittrockiana. – Differences from V. tricolor: flowers larger; stipules very wide at the base, with short lateral lobes. Difference from V. ×wittrockiana: petals narrower. In effect a back-cross; difficult to distinguish from small-flowered variants of the pansy.
N numerous records north to Tr Tromsø. S reported from Klm, SmI, Ög, Vsm and Mpd. F reported, at least, from V Kemiö, ES Valkeala and KP Raahe. – The material has not been critically revised. - Map (not in the book). TK

References To top

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