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Heracleum Taxa treated:
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 © Flora Nordica

by Lars Fröberg
(6b, 20090924)

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Heracleum L.

Linnaeus, Sp. Pl.: 249 (1753).
Hemicryptophytes. Plant bristly at least on stems and petioles. Leaves pinnate, with a broad, inflated sheath. Flowers ± zygomorphic (petals white) or not (petals greenish yellow). Fruit distinctly dorsiventrally flattened; carpophore filiform, divided; ridges straw-coloured to brown-yellow, 2 lateral wing-like and 3 low central ones (width of wings measured from the lateral veins); vittae from the apex of the fruit, clavate to saccate, red-brown (usually 4 dorsal ones c. 45–75 % as long as the mericarp and (0–)2(–4) shorter ventral ones).
Chromosome base number x=11; only diploids in Norden.
Taxonomy. The classification of Nordic Heracleum (apart from H. sphondylium) has hitherto been very uncertain. Among the names used for 19th and early 20th century records are H. giganteum Fisch. ex Horn., H. laciniatum Horn., H. palmatum Baumg., H. panaces L. and H. villosum Fisch.; however, all these names have now been shown to be inapplicable: the names H. giganteum, H. laciniatum and H. villosum are obscure because type material is probably lacking, and H. palmatum and H. panaces are probably related to (or conspecific with) H. sphondylium. In the late 20th century, the Heracleum taxon commonest in southern Norden was identified as H. mantegazzianum; the other fairly frequent taxon, with a more northern distribution, was referred to H. laciniatum or H. persicum (see further under H. persicum).
The four Nordic Heracleum species accepted here belong to three different groups. H. sphondylium belongs to section Heracleum, H. mantegazzianum and H. persicum belong to section Pubescentia Mand., and H. platytaenium belongs to section Villosa Mand. – See further under the closely related genus Pastinaca.
The giant species. Several of the impressive large Heracleum taxa were introduced to gardens, and escaped from cultivation already in the early 19th century; today, giant Heracleums are established and increasing in most countries of C and N Europe. A neighbour-joining analysis of molecular data (AFLP), made on material of giant Heracleum collected by local botanists in Europe and western Asia, was presented by Jahodova et al. (2007). The interpretation of the results was that the material represented three taxa tentatively called H. mantegazzianum, H. persicum and H. sosnowskyi. Unfortunately, no general taxonomic conclusions can be drawn from the study, due to method problems (inadequacies regarding vouchers and identification of taxa).
In Norden, Heracleum mantegazzianum and H. persicum are both rather frequent, and the closely allied H. sosnowskyi and H. pubescens are tentatively recognized from a few localities. Intermediates between H. mantegazzianum and H. persicum also occur, as well as some deviating morphotypes (see below). H. persicum is distributed in parts of The Middle East, south of Caucasus, and was introduced to European gardens early in the 19th century. It was first reported from Norden in N VFi Alta in 1836 and became widespread mainly in the northern and eastern parts during the 19th and 20th centuries. H. mantegazzianum is a Caucasian endemic which was discovered and brought to European gardens first in the 1890’s. The Western Greater Caucasus, where it occurs, was unavailable to explorers until 1872 due to war, and the species occurs at high altitudes which were difficult to reach (Jahdova et al. 2007). The late discovery of H. mantegazzianum is therefore understandable. It was first collected in Norden in 1896 (S Srm) and has since then expanded rapidly mainly in the southern parts (it has thus spread during a later period than H. persicum, and was not collected until after 1950 in the other Nordic countries).
Intermediates have been recorded at several localities in D, F, N and S. – Map of mantegazzianum / persicum intermediates (not in the book). – The taxa are not sympatric in their original distribution areas; the presence of intermediates (reported under various names, e.g. by Lid & Lid (2005) as H. mantegazzianum × tromsoensis) suggests that they hybridize easily and might be better treated as subspecies (but see further under H. persicum, Taxonomy). It is possible that several genotypes have been introduced to Europe, subsequently intermingling (not least in botanical gardens), giving rise to the large variation that can be observed in Norden today. In any case, a thorough evaluation of all taxa is needed, including material both from their original sites and from areas where they are introduced. This treatment was based mainly on herbarium material, which is largely very incomplete; since several diagnostic characters are unavailable even in good herbarium specimens, also living material must be studied to understand the variation.
The intermediates combine the characters of H. mantegazzianum and H. persicum in different ways. However, it cannot be excluded that some of them in the future may prove to be independent taxa. Specimens: D FyL Ballerup 1920, Glorup 1905 (forest), Sjæ Store Heddinge1869, Brn Christiansø 1964. N Ak Lørenskog 1944 (escaped in village), He Os 1991 (road bank), ST 3 localities in the 1990’s (roadside), NNo Bodø 2000 (roadside), Tr Tromsø 1906, 1993, 2000, Lyngen 1964 (brook near the docks). S Nrk Kil 1995, 2000 (garden relic) and Rinkaby 1955, Ång Bodum 2004 (garden relic). F V Lohja 1907, 1913, 1986 (Karnainen), U Helsinki 1923, 1949 (ruderal), 1960–70 and 2004 (Tuomarinkylä).
H. sosnowskyi Manden. (D Rundløvet Bjørneklo, S bredflikig jätteloka) was reported from D Sjæ København (Faurholdt & Hinke 2007), based on a specimen that appeared in the sosnowskyi-clade of the molecular analysis by Jahdova et al. (2007). It is characterized by leaflets with broad lobes, having broadly acute apices (broader than in H. persicum), rays and pedicels with dense papillae of H. mantegazzianum-type on the adaxial side, and by styles having a distinctly widened stigma. It is hapaxanthic and its stem has red spots as in H. mantegazzianum. The specimen fits well with material of H. sosnowskyi from Estonia (TAA), and also with the description of the species in Mandenova (1974). However, original material has not been consulted, and it is therefore only tentatively accepted here. Specimens: D Sjæ København (Ryparken 1987, 2003, Fælledparken 1973, Øresundshospitalet 1995, and the Botanical garden 1987). – Map H. sosnowskyi (not in the book).  
H. pubescens (Hoffm.) M. Bieb. (S mindre jätteloka) was reported from D (Wellendorf 1980) based on specimens determined by I. Mandenova. It is distinguished from H. mantegazzianum by having less elongated leaf-lobes and umbels with fewer rays (Mandenova 1974, Wellendorf 1980). The material has not been located, but some specimens from D, N and S may fit this description, and they are also characterized by having umbels with outer petals not distinctly larger than the others (distinctly larger in all other giant species) and purplish anthers; it is smaller than H. mantegazzianum and has umbels with only 9–40 rays. However, its identity could not be confirmed, since consulted material of H. pubescens in LE is heterogeneous and does not correspond to Mandenova’s description. Specimens: D ØJy Viborg 1941 (garden relic), Odder 1971, VJy Skjern 1968 (ditch), Sjæ Gentofte 1961, Langholmen 1965, N Vf Holmestrand 1922, Te Langesund 1951, Porsgrunn 2005 (large stand), S Srm Nynäs 1903 and Upl Danderyd 1945, 1981 (railway station). – Two other specimens with rather few rays, from S Klm Lofta 1971 (roadside) and Upl Danderyd 1954 (railway station), deviate from both H. mantegazzianum and the alleged H. pubescens in having fruits that are almost circular in outline and have distinctly wider vittae. – Map H. pubescens (not in the book).  
Kungsholm’ (S kungsholmsloka). A further deviating morphotype has been collected in D Brn Christiansø 1937, 1965 (possibly cultivated), NJy Lønstrup 1904 (brook), S Ög Jonsberg 1894 (possibly cultivated), and Upl Stockholm (escaped in Kungsholmen since 1980, and Djurgården 1943). It has rays and pedicels with stiff papillae but no hairs, and more narrow fruits with rather dense hooks (also on the surface). The leaves are more densely serrate with more acute teeth. It is closely allied to H. persicum but might be a separate species. The population on the island of Kungsholmen (S Upl Stockholm) was given the – incorrect – name H. stevenii by Lindberg (1983). The cultivar name ‘Kungsholm’ is here suggested for this entity. – Map H. ‘Kungsholm’ (not in the book).  
Documentation. Records of giant species are only rarely documented in herbaria. This has not only caused great problems in describing their variation and finding their correct names, but it has also made it difficult to follow their spread and to map their distribution adequately. The text on the distribution of H. mantegazzianum and H. persicum below is partly based on records not verified by herbarium specimens (but provinces from which vouchers have not been seen are given in brackets). For each species two maps are given, one based on verified records only, the other based on all accepted records.
Diagnostic characters. Important features for determination of Heracleum specimens are life form, leaf-shape and leaf indumentum, as well as indumentum on stem, rays, pedicels and ovaries/fruits, and width of vittae. Many specimens lack information on ”gross morphology” and are incomplete, consisting of only very small parts of leaves and umbels in flowering stage, leaving type of indumentum on different parts of the plant as the main character that can be studied. Indumentum on rays and pedicels may consist of papillae, hairs or both in varying densities. There are hairs of two kinds: flexuous translucent ones (glandular) and ± stiff whitish ones (eglandular), but intermediate types may also occur. The papillae vary in shape and may be translucent or whitish. Similar types of indumentum also occur on the ovaries/fruits. Length of indumentum on ovaries/fruits is rather constant in time, but vittae should be measured on ± ripe fruits. Indumentum on ovaries/fruits usually vanishes upon ripening.
A specimen should include at least the following: an umbel or some of the largest umbellules (preferably from the primary umbel) in flower, fruits that are as ripe as possible, and a piece of a lower leaf with rachis (preferably from the apical leaflet). Information on height, number of stems, pigmentation, leaf division and shape of umbels should be included if possible; a photograph may be very valuable.

Heracleum stevenii Mand. was reported from S Upl Stockholm (Lindberg 1983), based on material now referred to the cultivar ‘Kungsholm’, and from D Sjæ København (Madsen & Lyck 1991), based on material redetermined to H. platytaenium.

1 Leaves bristly on both sides (upper side sparsely so, lower side with bristles longer than 0.2 mm); pollen grains shorter than 48 μm; dorsal vittae thin (median ones 0.15–0.25 mm wide, lateral ones 0.2–0.4 mm wide)
- Leaves glabrous or puberulent at least beneath (upper side glabrous or sparsely bristly, lower side with up to 0.2 mm long hairs); pollen grains longer than 48 μm; dorsal vittae thick (median ones 0.4–1.2 mm wide, lateral ones 0.5–1.5 mm wide)
2 Leaves with rounded lobes, puberulent beneath and with sparse bristles above
- Leaves with acute lobes, glabrous above and glabrous or hairy (but not puberulent) beneath
3 Leaves with elongated, narrow lobes and teeth with concave sides; umbel rays with narrow, translucent, patent papillae and/or glandular hairs; ovaries/fruits with c. 0.5-1 mm long glandular hairs; dorsal vittae distinctly expanded
- Leaves with short, wide lobes and short teeth with ± convex sides; umbel rays with broadly triangular, whitish, ± ascending papillae, and usually also with non-glandular hairs; ovaries/fruits with whitish, non-glandular hairs usually longer than 1 mm; dorsal vittae slightly expanded
Nedan nya versionen. De två vita raderna här är osynliga om man inte kopplar bort stilar (css).
1 Leaves bristly beneath (bristles longer than 0.2 mm); pollen grains shorter than 48 μm; mericarps with thin dorsal vittae (median ones 0.15–0.25 mm wide, lateral ones 0.2–0.4 mm wide)
- Leaves glabrous or hairy beneath (hairs at most 0.2 mm), or rarely arachnoid; pollen grains longer than 48 μm; mericarps with thick dorsal vittae (median ones 0.4–1.2 mm wide, lateral ones 0.5–1.5 mm wide)
2 Leaves with broadly obtuse lobes, with sparse bristles above and arachnoid beneath
- Leaves with acute lobes, glabrous above and glabrous or hairy (but not arachnoid) beneath
3 Leaves with elongated, narrow lobes and teeth with concave sides; umbel rays with narrow, translucent, patent papillae and/or glandular hairs; ovaries/fruits with c. 0.5–1 mm long glandular hairs; dorsal vittae distinctly expanded towards the base of the mericarp
- Leaves with short, wide lobes and short teeth with ± convex sides; umbel rays with broadly triangular, whitish, ± ascending papillae, and usually also with eglandular hairs; ovaries/fruits with whitish, eglandular hairs usually longer than 1 mm; dorsal vittae slightly expanded towards the base of the mericarp

1. Heracleum sphondylium L.      map     ill.

Linnaeus, Sp. pl.: 249 (1753). – Type: Clifford Herbarium 103, Heracleum 1, fol. 3 (BM) lectotype, sel. by Reduron & Jarvis, Regnum Veg. 127: 53 (1993).

F ukonputki. N bjønnkjeks. S björnloka.

Non-aromatic biennial, to 1.4 m; taproot 7–16 mm thick. Stem solid, or secondarily hollow; basal part 4–9 mm thick, distinctly to indistinctly sulcate or angular, pale greenish or sometimes purplish, not or slightly glaucous, and usually densely bristly (sometimes with hairs or papillae interspersed); bristles on stems (lower part), petioles and rachises without or with a low, usually not purplish, well delimited base; upper internodes distinctly to indistinctly sulcate, with a sparse to dense cover of papillae or hairs (rarely with a few bristles interspersed). Leaves 2–3(–4) at the base and 3–5(–6) on the stem (the innermost basal one or the lowest stem leaf is the largest); sheath broad, sometimes purplish; petiole 8–27(–32) cm; blade 1-pinnate, (10–)15–31(–36) × 8.5–22 cm (length/width ratio 1.1–1.9), lower side usually rather densely covered with bristles, upper side sparsely covered with coarser bristles. Leaflets (1–)2(–3) pairs; angle leaflet/rachis (35–)45–70°. Apical leaflet 1–2-pinnatifid, with 1–3 pairs of lobes (sometimes elongated and narrow); petiolule 2–8 cm; blade 6–18 × 8–19 cm, with a length/width ratio of 0.7–1.1(–1.4); base usually cordate, sometimes truncate; lobe apices usually acute; margin crenate with usually purplish tips. Lateral leaflets 1–2-pinnatifid, with 1–2(–4) pairs of lobes; petiolule 0.5–5 cm long, sometimes sessile; blade 5–17 × (3.5–)5–12(–15) mm (length/width ratio 0.8–1.7); base broadly and often obliquely cuneate to cordate.
Umbels flat to slightly convex; peduncle 10–31 cm; rays straight or bent inwards, 5.1–10.5 cm, usually densely papillose on the adaxial side, with narrow, acute and translucent papillae often interspersed with a few short, glandular hairs. Bracts absent (more rarely up to 7, persistent). Umbellules 8–24(–34); pedicels 0.6–1.5(–2.1) cm, usually densely papillose (sometimes also with sparse glandular hairs) on the adaxial side. Bractlets 2–10, persistent, 2–15 × 0.2–0.9(–1.2) mm, usually hairy, without a membranous margin. Flowers 24–38(–48) per umbellule; sepals 0–0.3 mm; petals variable in size and colour (see subspecies); filaments 2–4 mm; anthers 0.7–0.9 mm. Pollen grains 38–47 × 19–26 μm (length/width ratio 1.6–2.2). Fruit obovate to elliptic in outline. Mericarps 5.8–9.5 × 4.5–6.8(–7.7) × 0.4–0.8(–1) mm (length/width ratio 1.1–1.6); wings 0.4–0.7 mm wide; dorsal vittae not expanded at the apex, median ones 3.5–5 × 0.15–0.25 mm, lateral ones 3–5 × 0.2–0.4 mm; stylopodium flattened, 1.1–1.6 mm wide; style 0.7–1.5(–2.2) mm, directed upwards to slightly outwards. – Mid-summer to late summer.
2n=22 (F U); 2n=22 + 0–3B (S Sk 5, Srm). – [2n=22]
Distribution. Nem–MBor(–NBor). – Resident in most lowland areas in mainland Norden, casual in S Lapland below the mountains; also I IVe.
Europe except the Mediterranean and the northernmost parts; W Siberia and N Africa. Introduced in North America, South America and New Zealand.
Habitat. Dry to moist, nutrient-rich, mull-rich, clayey or sandy ground in sun-exposed to shaded places. Usually in man-made sites, such as roadsides, railways, overgrowing fields, pastures and ruderal places, but also in seminatural sites, such as woodland margins, glades and seashores. Sometimes forming large populations, e.g. along roadsides and railways; perhaps favoured by fertilization.
Biology. The seeds are probably mainly wind-spread. – Many specimens have a reduced pollen fertility, although their morphology does not indicate hybridization between the subspecies. Weimarck (1978) reported a reduced pollen fertility in H. sphondylium from various sites in Europe, which was later explained by translocation heterozygosity (Weimarck et al. 1979). There are also reports of B-chromosomes in several of the studied populations, but no correlation was found between B-chromosomes and reduced fertility, neither on the male nor on the female side (Weimarck 1978).
Variation. Heracleum sphondylium varies extensively, e.g., in size, leaf shape and division, colour and degree of elongation of outer petals, and in the occurrence and length of fruit indumentum. The species has been divided into 9 subspecies in Europe (Brummitt 1968). Two of these occur in Norden, viz. subsp. sphondylium and subsp. sibiricum; subsp. sphondylium is distributed in the south and southwest (archaeophytic or perhaps native in D and western N), subsp. sibiricum has a more northern and eastern range and is much more common, and intermediates are frequent in eastern D, southern S and western N. The intermediates show a significant variation, combining the characters of the subspecies in different ways. The taxa have often been treated at specific level (e.g. Hämet-Ahti et al. 1998, Lid & Lid 2005), but are better regarded as subspecies since no reduced fertility has been found in intermediates.
Specimens with papillose fruits occur both in subsp. sphondylium (= var. chaetocarpoides Gawł.), subsp. sibiricum (= var. chaetocarpum Thell.) and intermediates, and the varieties are not accepted here because papillose fruits are not correlated with any other character in either subspecies.
Hybridization. Hybrids of Heracleum sphondylium are known with H. mantegazzianum and H. persicum.
Similar taxa see Angelica archangelica, A. sylvestris, Levisticum officinale and Pastinaca sativa.

1A. subsp. sphondylium   map    

H. sphondylium subsp. australe (Hartm.) Ahlfv. (1901). – H. sphondylium var. australe Hartm. (1838)..

D Almindelig Bjørneklo. F etelänukonputki. N kystbjønnkjeks. S vit björnloka.

Apical leaflet 8–17 × 9–19 cm. Bractlets (2–)5–10; size 5–15 × 0.3–0.9(–1.2) mm. Outer flowers of outer umbellules zygomorphic; petals white (sometimes with a violet tinge), 3–8.5 × 3.5–8.5 mm, bifid (apical cut 1.5–4 mm deep), usually with short hairs on the outer side. Fruit usually densely hairy, rarely papillose (indumentum sometimes destroyed during the drying of specimens).
Distribution. Nem–BNem. – Resident mainly in the south; archaeophytic or perhaps native in D and western N and S Sk; elsewhere brought in later via docks and railways, and probably also with grass seed and cereals. – Verified occurrence (frequency, however, based on both confirmed and unconfirmed records): D common to fairly common in ØJy, SJy, FyL and LFM, elsewhere scattered. N around Oslofjorden (ballast places in Øf Fredrikstad 1891 and Vf Tønsberg 1894), Te Tinn and Tokke (inland), and along the coast, rare from Vf Larvik to VA Kristiansand, scattered to fairly rare from western VA to MR (also in the fjords), and rare from northern MR to NT Grong (railway). S rare to scattered, but unevenly distributed; mainly in the southern lowlands (fairly common in western Sk) north to Vrm Karlstad, Dlr Borlänge and Ång Örnsköldsvik; probably mainly a late incomer but early established in e.g. Bl Karlshamn since 1871, Klm Kalmar since 1872, and Srm Hölö (Tullgarn) since 1864. first recorded from V Turku 1860’s; fairly rare in the southern provinces north to PH Jyväskylä; on ballast sites in U Pernaja 1903–64 and Porvoo 1937; as a German wartime incomer in several harbour towns at the western coast, and on loading places and camp sites in ite north (long surviving at least in EP Vaasa, PeP Tornio, Kn Hyrynsalmi and Ks Kuusamo); otherwise mostly on roadsides, yards and in gardens, now resident at least in V Karjaa, U Helsinki, EK Kotka, St Vammala, EH Hattula and ES Kouvola. I IVe Reykjavik 2009 (introduced with soil). – Also published from S Öl (Bringer 2006), Dls (Andersson 1981), and Vsm (Malmgren 1982), but vouchers are either not present, or have been redetermined.
W and C Europe (e.g. the Alps), N Africa.
Habitat. Roadsides, railways, pastures, woodland margins and glades, parks, gardens and ruderal places; earlier also ballast places, and in F at German loading places and camp sites from the second world war (see distribution).

1B. subsp. sibiricum (L.) Simonk.   map    

Simonkai, Enum. Fl. Transs.: 266 (1887). – H. sibiricum L., Sp. pl.: 249 (1753). – Type Linnaean Herbarium 352.5 (LINN) lectotype, sel. by Reduron, Nordic J. Bot. 22: 84 (2002).
H. sphondylium subsp. flavescens (Willd.) Soó (1973). – H. flavescens Willd. (1798).

D Grønblomstret Bjørneklo. F idänukonputki. N sibirbjønnkjeks. S sibirisk björnloka.

Apical leaflet 6–14 × 7.5–12 cm. Bractlets (0–)3–7; size 2–7 × 0.2–0.5(–0.7) mm. Outer flowers of outer umbellules not or slightly zygomorphic; petals green-brown or brown-yellow (sometimes with a violet tinge), 1.7–2.6 × 1.1–2.4 mm, entire, glabrous. Fruit glabrous or sparsely to rather densely papillose, never hairy.
2n=22 (F V).
Distribution and habitat. Nem–MBor. – Resident in most parts of Norden. Held to be native or archaeophytic in southern and central N and S but a recent introduction in D (except Sjæ) and F (except the southwestern archipelago); for habitats see the species. – D scattered in Sjæ (more common than subsp. sphondylium), rare in LFM, eastern and northern Jylland and Brn. N fairly common to scattered in the southeast, throughout Op, in western He and in ST; rare on the western coast and north of southernmost NT. S throughout the distribution area of the species. F throughout the country; apparently native in A and possibly in southwestern V; elsewhere a fairly early introduction of eastern origin, resident in all provinces except EnL. – Also reported from I IVe Reykjavik (Holmström 1994), but no vouchers seen.
N and E Europe, W Siberia.

Variation. Specimens with narrow-lobed leaves and entire to coarsely crenulate margins (e.g. from S Sk, Öl, Srm and Upl) have been recognized as var. angustifolium auct., but no correlation was found with other characters.

2. Heracleum mantegazzianum Sommier & Levier   map: total / verified     ill.

Sommier & Levier, Nuovo Giorn. Bot. Ital., nov. ser. 2: 79 (1895). – Type: Caucasus, Abkhazskaya [Abchasia], 1890, leg. Sommier & Levier nr. 68 (FI) lectotype, sel. by Ochsmann, Feddes Repert. 107: 585 (1996).
H. pubescens auct. scand., non (Hoffm.) Bieb. (1819).

D Kæmpe-Bjørneklo. F kaukasianjättiputki. N kjempebjønnkjeks. S jätteloka.

Literature. Ochsmann 1996, Often & Graff 1994, Pysek et al. 2007, Tiley et al. 1996.
Hemicryptophyte (hapaxanthic). Plant to 2.2–3.2 m, often with a sharp odour. Stem usually single, hairy, hollow; basal part 50–100 mm thick, usually sulcate, with purplish patches and bristle-like hairs (towards the apex with softer hairs); bristles on stems (lower part), petioles and rachises with a low to high, usually dark purplish, well delimited base. Leaves with a rather broad, usually purplish sheath; petiole 40–90 cm; blade 1-pinnate (almost ternately divided), 80–130(–170) × 90–150 cm, with a length/width ratio of 0.7–1(–1.4), lower side densely to sparsely covered with short hairs or glabrous, upper side glabrous. Leaflets 1–2 pairs. Apical leaflet 2-pinnatifid, with 3–4 pairs of primary lobes; petiolule 3–10 cm; blade 16–64 × (17–)23–72 cm (length/width ratio 0.7–1.1); base truncate to deeply cordate; margin doubly dentate to doubly serrate, with acuminate teeth; lobe apices usually long, narrowly acute to acuminate.
Umbels flat to slightly convex, 9–15 cm high and 25–60 cm wide; rays straight or bent inwards, 14–32 cm, on the adaxial side with translucent, patent papillae, and/or densely hairy, with long or short, ± flexuous glandular hairs. Bracts (0–)10–18, persistent. Umbellules 60–120; pedicels 1–3.5 cm, on the adaxial side with papillae and hairs as in the rays (sometimes more densely hairy). Bractlets 10–18, persistent, 7–15(–22) × 0.5–1.3 mm, slightly to distinctly hairy. Flowers (28–)34–73 per umbellule; sepals 0.3–0.9(–1.2) mm; petals 6–10.5 × 6–11(–13) mm (length/width ratio 0.6–1.4), bifid (apical cut 3–7 mm deep), with 2–3.5 mm wide lobes and indistinct to distinct veins; filaments (2.5–)3.5–5 mm; anthers 0.9–1.4 mm. Pollen grains 50–74 × 28–42 μm (length/width ratio 1.3–2.4). Fruit obovate in outline, with a sparse to dense cover of c. 0.5–1 mm long glandular hairs, sometimes also with minute, upwards directed hooks on the lateral parts. Mericarps 8.5–15 × 5.5–9.5 × 0.6–1.4 mm, with a length/width ratio of 1.2–1.7(–2); wings 0.6–1.2(–1.5) mm wide; dorsal vittae distinctly expanded at the apex, the median ones 5–9.5 × 0.7–1.2 mm, the lateral ones 4.5–8.5 × 0.8–1.5 mm; stylopodium ± conical, 1.2–2.3 mm wide; style 1.8–3.7 mm, directed ± outwards. – Early summer to mid-summer.
Distribution. Nem–MBor. Alt. N NT 380 m. Heracleum mantegazzianum was introduced as an ornamental; the first verified record of the species as an escape is from 1903 (S Srm Nynäshamn). It has increased much in the southern and western parts of the area, mainly during the second half of the 20th century (still increasing in N and F). – D first verified record FyL Hindsholm 1951; scattered to fairly common, but more scarce in southern and western Jylland (no specimens seen from ØJy, SJy, LFM and Brn). N first verified record Ho Fana 1958; according to Fremstad & Elven (2006) scattered to fairly common in the southeast north to He Ringsaker and Op Gjøvik, and along the coast from AA Arendal to VA Farsund (absent in Te); rare to fairly rare on the western coast and in the fjords from Ro Strand to NT Nerøy (no specimens seen from He, Op, Bu, Vf, AA, VA and ST). S scattered to fairly common (but unevenly distributed) in the southern and central parts, north to southern Vrm, Dlr Rättvik and Mpd Njurunda (no specimens seen from Öl, SmI, Vg, Dls, Vrm and Vsm). F first verified record EH Valkeakoski 1975; fairly rare to fairly common north to PeP Rovaniemi and Ks Kuusamo; resident at least in the southwestern mainland provinces (no specimens seen from A, V and U). I casual in INv Broddadalsá 2007 (also reported from INo 3 localities around Akureyri, ISu 3 localities in Rangárvallasysla, and as casual in IVe Reykjavik, but no specimens seen). Fa Sandur 1989 (casual on cemetery, as H. pubescens; no specimen seen). – Uncertain records from N Tr Tromsøya and Kvaløya (Often 1994, Alm et al. 2004; material in O is intermediate between H. mantegazzianum and H. persicum).
The Caucasus; introduced as an ornamental in most continents, now regarded as a pest at least in N and C Europe.

Habitat. Sun-exposed to rather shaded, rather moist, nutrient-rich habitats; indifferent to soil pH. Common in man-made sites, such as roadsides, construction areas, landfills, railway yards, dumps, gardens and parks; frequently also in seminatural sites such as deciduous and mixed woodland, unmanaged grassland, seashores, lake shores and along rivers. In some areas (e.g., S parts of Sk and Srm/Upl Stockholm area) forming dense and large stands.

Biology. Heracleum mantegazzianum is mainly hapaxanthic, and the age of flowering individuals ranges from 2–7 years. It is andromonoecious, self-compatible and protandrous. The seeds are spread by wind (mainly over short distances), water and human activities (Moravcová et al. 2007). The germination rate is very high under favourable conditions; the seed bank is not long-persistent.
The species contains furanocoumarins which, together with UV radiation, may cause serious skin injuries (photodermatitis; Hattendorf et al. 2007). Mechanical and chemical methods are used to control the species, but grazing by sheep is considered the most effective means. Aphids (e.g. Anuraphis subterranea Walker, Paramyzus heraclei Börner), curculionids (e. g. Lixus iridis Olivier), the lepidopteran family Depressariidae and the dipteran family Agromyzidae are the most important of the invertebrates feeding on H. mantegazzianum (Hansen et al. 2007). In its native area, H. mantegazzianum is the target of several parasitic fungi (e.g. Phlaeospora heraclei (Lib.) Petr., Ramulariopsis sp. and Phomopsis sp.), but few of them occur in the introduced range (Seier & Evans 2007).
Variation. Specimens with glabrous leaves have shorter hairs in the inflorescence than specimens with hairy leaves. – See also under H. persicum.
Hybridization. Hybrids of Heracleum mantegazzianum are known with  H. sphondylium (see also ’The giant species’).
Similar taxa. Heracleum mantegazzianum differs in habit from H. persicum, which usually has several stems. Further, H. persicum has a base that is ± continuously purple, usually with bristles not having distinctly swollen bases, less elongated leaf-blades with more (2–4) pairs of leaflets, and umbels that are usually more convex, especially at anthesis. See also the key.

3. Heracleum persicum Desf. ex Fisch.       map:  total / verified     ill.

Fischer, Ind. sem. horti Petrop. 7: 50 (1841). – Described on cultivated material (from Iran).
H. laciniatum auct. scand., non Hornem. (1813).
H. tromsoensis Elven (2005), nom. nud.
D Hårfrugtet Bjørneklo. N tromsøpalme. F persianjättiputki. S tromsöloka.
Literature. Alm & Jensen 1993, Often & Graff 1994.
Hemicryptophyte (perennial). Aromatic plant, to 1.8–2.8 m; odour reminiscent of anise. Stems 1–5, hollow, sparsely to densely hairy with bristle-like, short hairs, sometimes with small purplish patches; basal part 30–40 mm thick, usually sulcate, usually continuously purplish, the colour gradually thinner upwards or sometimes disintegrating into small purplish spots; bristles on stems (lower part), petioles and rachises without or with a low, usually not purplish, well delimited base. Leaves with a rather broad, usually purplish sheath; petiole 55–100 cm; blade 1-pinnate, 43–120 × 34–80 cm (length/width ratio 1.1–1.5), lower side densely covered with short hairs, upper side glabrous. Leaflets (1–)2–4 pairs. Apical leaflet usually 2-pinnatifid, with 2–4 pairs of primary lobes; petiolule 7–11 cm; blade 21–42 × 19–44 cm (length/width ratio 0.9–1.2); base truncate to deeply cordate; margin usually obtusely serrate; lobe apices short, broadly acute.
Umbels ± convex, 10–15 cm high and 30–50 cm wide (at anthesis); rays straight or bent inwards (at anthesis usually distinctly so), 8–22 cm, on the adaxial side sparsely to densely covered with triangular, whitish, ± ascending papillae, and usually also sparsely to densely covered with rigid, ± ascending hairs. Bracts 10–18, persistent. Umbellules 35–84; pedicels 1.3–3.5 cm, with similar indumentum on the adaxial side as the rays but usually more densely hairy. Bractlets 10–15, persistent, 3–10 × 0.2–0.8(–1.1) mm, distinctly hairy. Flowers (34–)40–80 per umbellule; sepals 0.2–1 mm; petals 6.5–14 × 8.5–15 mm (length/width ratio 0.7–1.2), bifid (apical cut (2–)3–8 mm deep), with 3–5 mm wide lateral lobes and usually distinct veins; filaments 3–4.5 mm; anthers 0.9–1.3 mm (stamens sometimes reduced and sterile). Pollen grains 51–66 × 24–33 μm (length/width ratio 1.6–2.2). Fruit oblong in outline, with a dense cover of flexuous hairs longer than 1 mm, sometimes also with lateral, minute, upwards-directed hooks. Mericarps 8–14 × 6–9.5 × 0.5–1.2 mm (length/width ratio 1.2–1.8); wings 0.6–1.1 mm wide; dorsal vittae slightly expanded at the apex, the median ones (4.5–)6–8.5 × 0.4–0.9 mm, the lateral ones (4–)5.5–8 × 0.5–1 mm; stylopodium flattened, 1.7–2.8 mm wide; style 1.3–3 mm, directed ± outwards. – Early summer to mid-summer.
Distribution. Nem–NBor. Alt. N ST 660 m. Heracleum persicum has long been in cultivation as an ornamental in the Nordic countries (known since 1836 in N VFi Alta, probably since the 1850’s in N Tr Tromsø), but there are no records of escaped occurrences in those areas until 1901 (cf. Alm & Jensen 1993); the first verified Nordic escape record is from F U Sipoo 1871. The species has increased much in northern and central N and perhaps also in southwestern F. – D Sjæ Jonstrup 1888, Roskilde since 2002 (Bognæs on seashore); casual in NJy Koldby 1937. N first verified record Tr Tromsø 1899 (cf. Notø 1901); according to Fremstad & Elven (2006) scattered to fairly common south to He Alvdal and Ho Bergen (casual in the southern provinces); Ak Asker 1941, Nes 1995 (cf. Often 1995) and Oslo 1955, 1996, He Ringsaker 1995, Os 1995, 1997, Op Lillehammer 1944 and Øyer 2005 (no specimens seen from Ho). S recently introduced in the northern provinces from northern N and subsequently escaped (cf. Often & Ericsson 1996); ÅsL Vilhelmina area, LyL Stensele and Tärna, PL Arvidsjaur, Vb Skellefteå and Umeå (no specimens seen), Upl Forsmark 1955 (large population at the castle), Klm Högsby 1935 (escaped in garden), Bl Ramdala 2000 (garden relic) and Sturkö 2003. F fairly rare north to OP Kiiminki and Ks Salla (resident only in V, U and EH; no specimens seen from EK, EP, PH, PS, PK, Kn and PeP). I INo Akureyri since 1978 (escaped from botanical garden; no specimens seen).
Iran, Iraq and Turkey.
Habitat. Sun-exposed to shaded, nutrient-rich habitats. Mostly in man-made places such as roadsides, railways, ruderal places, gardens and parks; at least in N and F sometimes also in seminatural habitats such as deciduous woodland, ungrazed grassland and shores. At several localities, e.g. in N Tr Tromsø, forming dense and large stands.
Biology. Heracleum persicum is a truly perennial herb, producing flowering shoots repeatedly for several years; it may survive long in a locality even if sexual reproduction fails (in contrast to H. mantegazzianum, which is hapaxanthic and depends on seed reproduction for survival). Pollen fertility varies extensively (see under Taxonomy). Seed reproduction seems to be less vigorous in H. persicum than in H. mantegazzianum, as would be expected, at least in the southern parts of the area; however, in N Tr Tromsø, seed reproduction is extensive, and H. persicum has expanded enormously (also hybridizing with H. sphondylium subsp. sibiricum). According to Often & Graff (1994) only the seeds of the primary umbel are developed in H. persicum, while those of secondary and tertiary umbels are aborted.
Taxonomy. The Nordic material of Heracleum persicum has raised great interest and caused much confusion; the species has often been taken for H. mantegazzianum. In northern N (Nordhagen 1940, Lid 1963) and in F (Hiitonen 1933) it was earlier recognized under the name of H. laciniatum Hornem. Brummitt (1968) suggested that the Nordic material belongs to H. persicum, and that name was adopted for material from F in Hämet-Ahti et al. (1984).
Original material of H. laciniatum has not been found, but according to the protologue in Hornemann (1813, p. 279) that species has entire, lobed leaves that are tomentose beneath, and it is not likely to be conspecific with this taxon.
Øvstedal (1987) concluded that the material in northern N was not conspecific with H. persicum; he based his judgement on comparison with H. persicum material from Turkey differing in several characters, e.g., size and shape of the fruits, width of the vittae, shape and division of the leaves, and pollen size.
When more of the Nordic material is taken into account, and also H. persicum material from Iran, a comparison will show fairly good correspondence in most characters. Nordic fruits usually do not have the typical cuneate base of H. persicum from the Orient, and their vittae are proportionally slightly longer (the length of vittae in oriental H. persicum is 61–71% of the mericarp length, in Nordic material 68–76%). However, in leaf shape, in absolute size of fruits and vittae and in size of the pollen grains (52–60 × 25–30 μm in H. persicum according to Øvstedal 1987), the restricted Turkish and Iranian H. persicum material studied falls within the greater variation range of the Nordic material. Also in important diagnostic characters not mentioned by Øvstedal, such as the shape of the dorsal vittae and the indumentum on rays and fruits, Nordic plants agree with oriental H. persicum material.
Nordic H. persicum varies extensively, with no clear limit towards H. mantegazzianum. Even in fairly typical specimens the pollen fertility is frequently reduced (0–100%; above 80% in H. persicum from Turkey and in H. mantegazzianum), which suggests a hybrid origin. H. persicum is here defined as having stems, petioles and rachises without large red spots, leaves with crenate margins, rays and pedicels with whitish, acute, antrorse papillae and densely long-hairy ovaries/fruits with a fairly low stylopodium. Specimens deviating in any of these characters have been classified as intermediates. – Map of mantegazzianum / persicum intermediates (not in the book).
The true nature of the intermediates is uncertain. H. mantegazzianum is a Caucasian endemic (H. persicum is not known from the Caucasus) which was discovered and brought to European gardens in the 1890’s. It was first collected in Norden in 1896 (in S Srm; it was not collected until after 1950 in the other Nordic countries). Thus, the older Nordic material would not be expected to include any intermediates, but it does (e.g., from D Sjæ 1869). Other possible explanations to the great variation in Nordic H. persicum may be hybridization with other allied species, either at their original sites or in cultivation. Also, genetic drift may have added to the variation seen today.
Variation. A deviating morphotype has been collected in F U Helsinki 2001 (Suomenlinna), EH Janakkala 1959, Luopionien 1966 and S Nb Edefors 1997 and LyL Lycksele 1993 (both in grassland). It has more densely hairy lower leaf surfaces; the rays and pedicels lack hairs and have papillae that are similar to those in H. mantegazzianum, and the ovaries/fruits have shorter hairs than H. persicum. Other characters fit with H. persicum, and the specimens are therefore tentatively referred to this species. – See also under The giant species. – For background data see map of Heracleum cf persicum (not in the book).
Hybridization. Hybrids of Heracleum persicum are known with  H. sphondylium (see also ’the giant species’).
Similar taxa see Heracleum mantegazzianum (2).

4. Heracleum platytaenium Boiss.   map    

Boissier, Ann. Sci. Nat. ser. 3 (1): 331 (1844). – Described from Turkey.
S hörsneloka.
Literature. Davis 1972.
Hemicryptophyte (short-lived hapaxanth). Slightly aromatic plant up to 2 m. Stem hairy, with bristle-like hairs, hollow; basal part at least 20 mm thick, sulcate. Leaves with a rather short sheath; petiole 15–30 cm; blade large, simple or 1-pinnate with 1 pair of leaflets, lower side with a dense cover of arachnoid hairs, upper side sparsely bristly. Apical leaflet 2-pinnatifid, with 2–3 pairs of primary lobes; petiolule 5–10 cm; blade 21–24 × 24–25 cm (length/width ratio 0.8–1); base cordate; lobe apices broadly obtuse (sometimes apiculate); margin dentate with small teeth.
Umbels convex, 10 cm high and 25 cm wide. Bracts absent. Umbellules 34–42; rays straight, 11.5–16 cm, on the adaxial side with ± antrorse, hyaline to whitish papillae, without hairs. Bractlets 12, rather short. Flowers 48–60 per umbellule; pedicels 1.7–2.2 cm, with smaller and more obtuse papillae on the adaxial side; petals 2.5–5.5 × 1.5–3.5 mm, bifid (apical cut 1.2–3 mm deep); filaments 4–4.5 mm; anthers 0.9–1.2 mm. Pollen grains 65–67 × 30–34 μm. Fruit oblong in outline, with a sparse to dense cover of c. 0.5 mm long glandular hairs, with an odour of Citrus. Mericarps 9.5–13.5 × 7.5–10.5 × 0.8–1 mm (length/width ratio 1.3–1.4); wings 0.9–1.2 mm wide; dorsal vittae broad, the median ones 6.5–7 × 1.2–1.5 mm, the lateral ones 5.5–6 × 1.2–1.5 mm; stylopodium low-conical, 1.7–2 mm wide; style 3–3.5 mm, deflexed. – Early summer.
Distribution and habitat. Grown as an ornamental; probably escaped or remaining from cultivation. – D NJy Fjerritslev 1994, Sjæ Jonstrup 1886, Roskilde 1950 (road embankment), København 1981. S Gtl Hörsne (large population on roadside since 1950’s), Nrk Askersund 1990–2001 (garden relic).


Heracleum mantegazzianum × sphondylium subsp. sphondylium. – Similar to H. persicum × sphondylium, but stem and petioles ± red-spotted. Rays and pedicels densely covered with translucent, patent papillae and soft, flexuous glandular hairs (no opaque, acute papillae) – Pollen sterile.
Sjæ Roskilde 1911 (moist slope). S Sk Lund 2001 (spontaneous in botanical garden). – H. mantegazzianum × sphondylium has also been recorded from N ST Trondheim (Lid & Lid 2005), but specimens have been redetermined to H. persicum × sphondylium. – Map (not in the book).
Heracleum persicum × sphondylium. – N polarpalme. – Variable, with some specimens more similar to H. persicum and others similar to H. sphondylium. Leaf-blades with hairs intermediate in stiffness, upper side glabrous or with very few, minute bristles, especially along the edge, lower side with rather sparse hairs. Rays and pedicels covered with opaque, acute, patent to ascending papillae and sometimes also rather rigid, opaque hairs. Fruit usually with long hairs and short papillae mixed on the surface; mericarps 9–12 × 7–9 mm; median vittae 0.2–0.4 mm wide; lateral vittae 0.3–0.7 mm wide. – Pollen sterile, but the hybrid is common and backcrosses with the parents in N Tr Tromsø.
N ST Trondheim since 1975 (5 localities), NNo Bodø 2000 (with subsp. sibiricum), Tr Tromsø since 1956 (resident and increasing; with subsp. sibiricum). S Bl Sturkö since 2003 (with subsp. sibiricum). F St Vammala 1986. – Map (not in the book).

Intermediates, deviating morphotypes and tentatively accepted taxa:

Heracleum mantegazzianum / persicum intermediatesMap (not in the book). 
Heracleum cf persicum – Map (not in the book).
Heracleum pubescens (Hoffm.) M. Bieb.  – Map (not in the book).
Heracleum sosnowskyi Manden.  – Map (not in the book). 
Heracleum 'Kungsholm' – Map (not in the book).  

References To top

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