7. Lemna L., Sp. Pl. 2: 970 (1753).
By: Himanchal T. Magar & Mohan Siwakoti
Taxon Description
Minute floating or submerged aquatic, scale-like herbs. Root single, emerging from the lower side of a frond. Fronds circular to lanceolate, flat or swollen abaxially, fronds with single root, veins 1–5(–7). Reproducing from 2 budding pouches, daughter fronds becoming detached or remaining attached. Monoecious. Inflorescences enclosed by spathe in one budding pouch. Flowers occurring in marginal clefts. Stamens 2, filaments slender, anthers bilocular. Gynoecium 1, ovules 1–7.
Taxon Statistics
Thirteen species in the world, nearly cosmopolitan. Two species in Nepal.
Key to Species
1a Leaf apex rounded. Root tip mostly rounded …………………………………………… 1. L. minor
b Leaf apex acute. Root tip usually sharp pointed ………………….…………….. 2. L. perpusilla
1. Lemna minor L.; Sp. Pl.: 970 (1753).
Hydrophace minor (L.) Bubani; Lenticula minor (L.) Scop.
हाँसको चिऊरा Hansko chiura (Nepali).
Aquatic herbs up to 7 cm, growing on freshwater ponds and slow-moving streams. Roots 0.5–15 cm, tip mostly rounded. Turions absent. Fronds free-floating, forming a small group of 1–8 individuals. Leaves elliptic to obovate, 2–6 X 2–4 mm, margin green, lustrous, sometimes reddish, rarely reddish on the lower surface, entire, base rounded, apex rounded, veins 3(–5), lateral veins widest apart near the middle part; conspicuous papillae near apex and above node on the upper surface.
Distribution: Nepal, W Himalaya, S Asia, E Asia, N Asia, C Asia and SW Asia; Europe, Africa and N America.
Altitudinal range: ca. 3000 m.
Ecology: Growing in damp flushes in meadow, patches on stagnant water.
Flowering: May–September. Fruiting: May–September.
Specimens are not available in KATH. Morphological characters were described from specimens deposited in E (Barcode-E00111666, E00111667) & floral characters were taken from the Flora of Bhutan.
2. Lemna perpusilla Torr., Fl. New York 1: 245 (1843).
Hydrophace perpusilla (Torr) Lunell.
Aquatic herbs, growing on still or slow-moving waters of swamps, ponds or lakes, 1–2 cm. Roots up to ca. 3.5 cm, tip usually pointed. Distinct turions absent. Fronds free-floating, forming a small group of 1 or 2–few individuals. Leaves ovate-obovate, 1–4 X 1–7 mm, margin entire, green, lustrous, greenish on the lower surface, base rounded, apex acute, veins 3, lateral veins widest apart near or distal to the middle part; conspicuous papilla near apex and above node on the upper surface.
Distribution: Native of N. America; naturalized in Nepal.
Altitudinal range: 600–2700 m.
Ecology: Aquatic, floating, fresh water, ponds, lakes, slow moving water.
Flowering: June–September. Fruiting: June–September.