2. Wolffia brasiliensis Wedd.
Pl.
98 g; Map 393
W. papulifera C.H. Thomps.
Fronds 0.5–1.6 mm long, usually punctate with small red or brown spots, the
upper surface concave and with a large central papule, the tip rounded. 2n=20,
40, 42, 50, 60, 80.
Scattered, mostly in the Ozark, Mississippi Lowlands, and Big Rivers Divisions
(eastern U.S. west to Texas, south to southeastern South America; West Indies).
Floating on shallow, stagnant water of ponds, lakes, sloughs, ditches, and
swamps, sometimes forming mats; sometimes stranded on mud by receding
waterline.