Turion Duckweed

Similar to Lemna minor but differentiated on the basis of fronds being obovate or slightly orbicular, with several distinct papillae on the mid line of the upper surface, whereas in Lemna minor the fronds are elliptic-oblong with mostly two papillae on the mid-line of the upper surface. The fronds in Lemna turionifera form rootless dark green turions.

I know of no specimens of Lemna turionifera from Maine, New HampshireSt. Pierre and Miquelon, or from New Jersey, but the species is to be expected there..

Fronds floating, orbicular-obovate-ovate, 1-33 x 0.5-2 mm, never becoming inflated, often with 3-7 papillae on the mid-line on the upper surface; pigmented spots absent from the upper surface but sometime present on the lower surface near the base of root; fronds usually with 3 nerves, forming small circular greenish to brownish rootless turions (similar to S. polyrrhiza). Floral pocket lateral, spathe ± closed; staminate flowers 2, each with single stamen; pistillate flower solitary; fruit not winged.

Roots shorter than 15 cm, tip mostly rounded; sheath not winged. Stipes white, small, often decaying. Fronds floating, 1 or 2--few, coherent in groups, obovate, scarcely gibbous, flat, 1--4 mm, 1--1.5 times as long as wide, margins entire; veins 3, greatest distance between lateral veins near or distal to above middle; papillae distinct on midline of upper surface (apical papilla scarcely larger than others); lower surface often red (more intensely so than on upper), coloring beginning at attachment point of root, upper surface (especially near apex) sometimes with red spots; air spaces to 0.3 mm; turions sometimes present, rootless, olive to brown, 0.8--1.6 mm diam., sinking to bottom. Flowers: ovaries 1-ovulate, utricular scale with narrow opening at apex. Fruits 0.5--0.6 mm, not winged. Seeds with 30--60 indistinct ribs, staying within fruit wall after ripening. 2n = 40, 42 (G), 50, 80.

Distribution: North America, Siberia, Turkey, Central and South East Asia, India and Pakistan.

St. Pierre and Miquelon; Alta., B.C., Man., N.B., Nfld. and Labr., N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon; Ala., Alaska, Ariz., Calif., Colo., Conn., Idaho, Ill., Ind., Iowa, Kans., Mass., Mich., Minn., Mo., Mont., Nebr., Nev., N.J., N.Mex., N.Y., N.Dak., Ohio, Okla., Oreg., Pa., R.I., S.Dak., Tex., Utah, Vt., Wash., W. Va., Wis., Wyo.; Mexico (Baja California); Eurasia.

Fl. Per.: April-July.

Flowering (occasional) summer.

Mesotrophic to --eutrophic, quiet waters, in continental, temperate regions; 0--3700m.

Lemna turionifera is a species of flowering plant belonging to the family Araceae.

The species is a floating freshwater aquatic plant, with one, two, three or four leaves each having a single root hanging in the water. Like its close relative Lemna minor, it reproduces primarily vegetatively. Unlike L. minor, however, the species is also capable of producing turions, which are starch-filled fronds that sink to the substrate and remain dormant until germinating when conditions are favorable.

Its native range is Northern Europe to Japan, Northern America.