|
1. Ludwigia L.
Linnaeus, Sp. pl.: 118 (1753).
Literature. Peng et al. (2005).
Glabrous aquatic perennials, prostrate to ascending, submerged (shoot and branch apices sometimes floating). Leaves opposite, petiolate; blade elliptic, subacute. Bracteoles present, flanking the base of the ovary. Flowers inconspicuous, single in leaf axils, sessile, actinomorphic. Sepals 4, persisting in fruit. Petals 4, very small and caducous, or absent. Stamens 4. Stigma capitate. Capsule short, not or scarcely opening. Seeds without a tuft of hair. – [2n=16]
Chromosome base-number x=8.
Similar taxa. The species of Ludwigia treated here are superficially similar to small-flowered species of Lythrum (Lythraceae); they differ, e.g., in lacking an epicalyx.
|
Ludwigia palustris (L.) Elliott 1817 ( Isnardia palustris L. 1753). S ludwigia. – Stem to 30 cm, rooting at the nodes. Bracteoles to 1 mm. Sepals 1–2 × 1–2 mm, acute to obtuse. Petals absent. Anthers c. 0.3 mm. Capsule oblong to obovoid. – [2n=16]
S Hl Östra Karup (Hemmeslöv) c. 1780 (shore of stream, probably spontaneous although ephemeral; Osbeck 1788), BhG Kville (Mörhult) 1910 (ballast; Almqvist 1914). – S, C and W Europe (north to the Netherlands and formerly to NW Germany), SW Asia, Africa, N and S America. - Distribution documentation (not in the book).
|
Ludwigia repens J.R. Forst. 1771 ( L. natans Elliott 1821). S sumpludwigia. – Stem to 50 cm, rooting at the nodes. Bracteoles longer than 1 mm. Sepals 2–5 mm, narrowly triangular, acuminate. Petals caducous, yellow, c. 1 mm. Anthers 0.5–0.6 mm. Capsule slightly more elongated than in L. palustris.. – [2n=32]
Grown as an aquarium plant, escaped in D NJy Brønderslev 1926. – Southern North America, northern S America. - Distribution documentation (not in the book). |
|