Lemmnaceae,. Duckveed Family. 
“inute alga-like aquatic plants, commonly floating on the surface 
of ponds and slow-moving streams and frequently forming extensive colonies, 
Plant body a disc-eshaped, leaf-like structure, a few millimeters long, 
from the under side of which arise 1 or more tiny rootlets, Reproduction 
is commonly vegetative by "budding" whence daughter plants are formed, 
The flowers (rarely produced) are borne on the under side and consist of 
a single flask-shaped ovary and 2 stamens, surrounded by tiny sac-like 
svathe, Yerianth none. Fruit a tiny inflated achene, 
O Rootlets several, forming a bundle near the center on 
4 the lower side of each "frond", ved—persath I. oe ae 
O Rootlets solitary from each "frond", green -teneath 2. Lema 
As the name indicates the Luckweeds are of considerable economic importance 
as duck food. Their habit in northern climates of sinking to the bottom 
of che body of water on which they are growing at the approach of cold 
weather while remaining afloat in warmer climates is of further biological 
interest as a factor in wild fowl migrations. 
J. Spirodela Schleid, 
Plant body disc-shaped. -.cotlets several, fascicled, arising near the 
center, each with a single strand of vascular tissue. Reproductive pouches 
2, near the base ot the frond. Spathe sac-like; inflorescence of 1 
pistillate and © staminate flowers. Fruit rounded-lenticular, the margin 
winged. 
le Se polyrhiza (Le) Schleid.e Greater Duckweed. Fronds obovate in outline, 
5-10 mn, long, green on the upper surface, faintly 5-12, mostly 7-veined, 
purplish beneath; rootlets commonly 5-8; rootcan conspicuous, acute. 
: y 
