2. Lemna turionifera Landolt in Aquatic Bot. 1: 355. 1975. Landolt, l.c. 18. 1980; Uotila, l.c. 67.
RIZWAN Y. HASHMI & SAOOD OMER
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.
Fl. Per.: April-July.
Holotype: U.S.A., Montana, Lincoln Co., 20 km west of Davensport, 19. 6. 1953, Wm. M. Hiesey (ZT) Live collection 6573.
Distribution: North America, Siberia, Turkey, Central and South East Asia, India and Pakistan.
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.