Lemna obscura |
Lemna minor |
|
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little duckweed |
common duckweed, lenticule mineure, lesser duckweed, small duckweed, smaller duckweed, water lentil |
|
Roots | to 15 cm, tip mostly rounded; sheath not winged. |
to 15 cm, tip mostly rounded; sheath not winged. |
Flowers | ovaries 1-ovulate, utricular scale with narrow opening at apex. |
ovaries 1-ovulate, utricular scale with narrow opening at apex. |
Fruits | 0.5–0.7 mm, not winged. |
0.8–1 mm, laterally winged toward apex. |
Seeds | with 10–16 distinct ribs, staying within fruit wall after ripening. |
with 8–15 distinct ribs, staying within fruit wall after ripening. |
Stipes | white, small, often decaying. |
white, small, often decaying. |
Fronds | floating, 1 or 2–5 or more, coherent in groups, obovate, flat or gibbous, 1–3.5 mm, 1–1.5 times as long as wide, margins entire; veins 3, greatest distance between lateral veins near middle; very distinct papillae near apex, some smaller indistinct ones on midline of upper surface; lower surface very often red colored (more intensely than on upper), coloring beginning at attachment point of root, lower upper surface sometimes with red spots; air spaces shorter than 0.3 mm; distinct turions absent. |
floating, 1 or 2–5 or more, coherent in groups, ovate, scarcely gibbous, flat, 1–8 mm, 1.3–2 times as long as wide, margins entire; veins 3(–5) (if more than 3, outer ones branching from inner ones), greatest distance between lateral veins near or proximal to middle; papillae not always distinct (one near apex usually larger); lower surface very seldom slightly reddish (much less than on upper), coloring beginning from attachment point of root, upper surface occasionally diffusely reddish; air spaces 0.3 mm or shorter; distinct turions absent. |
2n | = 40, 42, 50. |
= 40, 42 (B), 50, 63, 126. |
Lemna obscura |
Lemna minor |
|
Phenology | Flowering (occasional) spring–fall. | Flowering (rare) late spring–early fall. |
Habitat | Mesotrophic to –eutrophic, quiet waters, in temperate to subtropical regions with mild winters | Mesotrophic to –eutrophic, quiet waters, in suboceanic, cool-temperate regions with relatively mild winters |
Elevation | 0–800 m (0–2600 ft) | 0–2000 m (0–6600 ft) |
Distribution |
AL; AR; DC; DE; FL; GA; IA; IL; IN; KS; KY; LA; MD; MN; MO; MS; NC; NE; NJ; NY; OH; OK; PA; SC; SD; TN; TX; VA; WI; c Mexico; South America (Colombia, Ecuador); Hawaii
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AL; AR; AZ; CA; CT; DC; DE; FL; IA; ID; IL; IN; KS; KY; LA; MA; MD; ME; MI; MN; MO; MT; NC; ND; NE; NH; NJ; NM; NY; OH; OK; OR; PA; RI; SD; TN; UT; VA; VT; WA; WI; WV; BC; ON; QC; SK; SPM; w Eurasia; Africa; Atlantic Islands [Australia (introduced), Australia; introduced, New Zealand (introduced)]
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Discussion | Indication of this species in Newfoundland (H. J. Scoggan 1978–1979) probably refers to Lemna turionifera. A specimen in the Gray Herbarium from St. Pierre and Miquelon may represent Lemna minor or L. turionifera; its determination is questionable. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 22. | FNA vol. 22, p. 148. |
Parent taxa | Lemnaceae > Lemna | Lemnaceae > Lemna |
Sibling taxa | ||
Synonyms | L. minor var. obscura | |
Name authority | (Austin) Daubs: Illinois Biological Monographs 34: 20. (1965) | Linnaeus: Sp. Pl. 2: 970. (1753) |
Web links |
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