Amphicarpaea bracteata (L.) Fernald
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Annual to 1.5 m; stipules and stipellules ovate or lanceolate, striate; lfls 2–8 cm, ovate or rhombic-ovate, broadly rounded at base; infls peduncled from many of the axils, with broadly obtuse to subtruncate bracts and 2–many pale purple to whitish fls 12–18 mm; cal-lobes 1–2 mm; frs 1.5–4 cm, strigose at least on the sutures; 2n=20. Highly variable especially in pubescence, but scarcely divisible into vars. Abundant in woods and thickets; Que. and N.S. to Man. and Mont., s. to Fla. and Tex. Aug., Sept. (A. monoica; A. pitcheri)