Desmodium canadense is a perennial herb, to 2 m tall, one to several stems, from a brown root, aerial stem branched above, finely hairy above; stipules 0.5-0.9 cm long.
Leaves alternate, 3-parted, leaf stalk 0.2-2 cm long, stipules of leaflets 0.2-0.4 cm long, leaflet stalks (petiolules) 0.2-0.3 cm long, central leaflet 5-10 cm long, 2-3.8 cm wide, elliptic to egg-shaped, hairy below, dull green, margins entire, stalks 1-2 cm, hairy, much shorter than terminal leaflet.
Flowers rose-purple, becoming blue, 0.8-1.3 cm long, bilaterally symmetrical, bean-flower shaped, calyx bilaterally symmetrical; inflorescence a dense raceme at top of stem ; blooms July-Aug.
Fruit dry, jointed between seeds into 1-5 segments, upper suture slightly curved, lower suture of each segment rounded, surface densely hooked-hair y, segments breaking at joints between seeds. Seeds dispersed by sticking to fur or clothing (Matlack 1994), eaten by some birds and small mammals (Martin et al. 1951).
Wetland status: FAC.
Frequency in NYC: Very infrequent.
Habitat: Open woods, moist soil, river banks.