Lesser Duckweed

Nile region and oases.

Cosmopolitan, except Australia.

Some authors did not distinguish between Lemna aequinoctialis and L. perpusilla and used the latter name for both species.

Free floating; fronds pale green, obovate to oblong, flat on both surfaces, 1.5-6 x 0.7-3 mm, asymmetrical, upper surface mostly with a distinct papilla at apex and above node, obscurely 3-nerved; several individuals lying closely. Root solitary and winged, root cap acute. Flowering pocket lateral; spathe open, staminate flowers 2, pistillate flower 1, seed 8-26 ribbed.

Roots to 3 cm; tip usually sharp pointed; sheath winged at base (wing 1--2.5 times as long as wide). Stipes small, white, often decaying. Fronds floating, 1 or 2--few, coherent in groups, ovate-lanceolate, flat, 1--6 mm, 1--3 times as long as wide, margins entire; veins 3, greatest distance between lateral veins near or proximal to middle; 1 often very distinct papilla near apex on upper surface and 1 above node; anthocyanin absent, no reddish color; largest air spaces much shorter than 0.3 mm; distinct turions absent. Flowers: ovaries 1-ovulate, utricular scale open on 1 side. Fruits 0.5--0.8 mm, not winged. Seeds with 8--26 distinct ribs, falling out of fruit wall after ripening. 2n = 40, 42, 50, 60, 80, 84.

Distribution: Throughout all the warmer regions of both the hemispheres.

Fl. Per.: April-May.

Flowering (frequent) spring--fall. Mesotrophic to eutrophic, quiet waters in warm-temperate to tropical regions; 0--1300 mm; Ala., Ariz., Ark., Calif., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Miss., Mo., Nebr., N.Mex., N.C., Okla., S.C., Tenn., Tex., Va., Wis.; West Indies; Central America; South America; s Eurasia; Africa; Atlantic Islands; Indian Ocean Islands; Pacific Islands; Australia.

Lemna paucicostata Hegelmaier

These minute plants have the smallest flowers of any plant and are among the most invasive species. They are 1-4 mm in diameter and roughly ovate. They can live in any habitat and are commonly fed on by ducks and some frogs.

Range Description: This hydrophyte is widespread in freshwater habitats in tropical and subtropical countries across Africa, Asia, Oceania and America. Countries - Native: Afghanistan; Argentina; Aruba; Australia (Coral Sea Is. Territory, Northern Territory, Western Australia); Barbados; Belize; Benin; Bermuda; Bolivia; Brazil; Burkina Faso; Burundi; Cameroon; Cape Verde; Cayman Islands; Central African Republic; Chad; China (Anhui, Fujian, Guangdong, Guizhou, Hebei, Henan, Hubei, Jiangsu, Jiangxi, Liaoning, Qinghai, Shaanxi, Yunnan, Zhejiang); Christmas Island; Colombia; Congo; Congo, The Democratic Republic of the; Costa Rica; Côte d'Ivoire; Cuba; Dominican Republic; Ecuador; Egypt; El Salvador; Fiji; Gambia; Ghana; Guatemala; Guinea; Guinea-Bissau; Guyana; Haiti; Honduras; India; Indonesia (Bali, Kalimantan, Lesser Sunda Is., Maluku); Jamaica; Kenya; Lesotho; Liberia; Madagascar; Malawi; Malaysia; Mauritius; Mexico; Mozambique; Namibia; Nepal; New Caledonia; Nicaragua; Niger; Nigeria; Panama; Paraguay; Peru; Philippines; Puerto Rico; Réunion; Russian Federation (Khabarovsk); Rwanda; Senegal; Seychelles; Sierra Leone; South Africa; Suriname; Swaziland; Taiwan, Province of China; Tanzania, United Republic of; Thailand; Togo; Tonga; Trinidad and Tobago; Uganda; United States; Venezuela; Viet Nam; Virgin Islands, British; Virgin Islands, U.S.; Zambia; Zimbabwe"

aequinoctialis: of the equinox (possibly referring to the flowering time)

Minute free-floating aquatic, often forming extensive colonies. Thallus pale green, more or less ovate, 1.5-4 mm, asymmetric, obscurely 3-veined. Root solitary.

Common and widespread in Zimbabwe except the most humid regions of the Eastern Highlands.

Lemna aequinoctialis, the lesser duckweed, is a tiny, floating aquatic plant found in quiet waters in tropical and subtropical regions. Fronds are generally 3-nerved, green, up to 6 mm long. Flowers are 1-ovulate, the small utricular scale open on one side. Seeds have 8–26 ribs.