Stems 10-30 m, the younger parts hairy; lfls broadly ovate to subrotund, 10-15 cm, often 2-3-lobed, hairy beneath; infls 1-2 dm, the axis and pedicels densely sericeous; fls 2-2.5 cm; lowest cal-lobe 8-12 mm; standard yellow at base; fr 4-5 cm; 2n=22, 24. Native of Japan, China, and Korea, cult. for forage and erosion-control in se. U.S., escaped and extending n. into the s. part of our range, sometimes even to Mass., N.Y., and O. Late summer. (P. thunbergiana)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.