Wolffia brasiliensis is a minute monocotyledon (but apparently larger than W. columbiana), free floating plants without stems, leaves or roots, about 0.1 cm diameter, asymmetrically elliptic, upper surface with a small, conical point, dark green, sometimes brown, lower part pale green, rounded, floating low in water, colonial by budding.
Flowers rarely produced (see W. columbiana).
Wetland status: OBL.
Frequency in NYC: Very infrequent.
Habitat: Quite ponds.
Notes: Much smaller than Lemna and without roots. Listed as W. brasiliensis by USDA.plants (2006).