Lotus purshianus Clem. & E.G.Clem.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Species Description - Annual, ± erect, branching, 2–6 dm, lvs subsessile; stipules represented by minute glands; lfls 3, 1–2 cm, the terminal one stalked; fls solitary in the upper axils; pedicels about equaling the lvs, bearing a terminal bract as long as the ft; cor 5–8 mm, at first ochroleucous, turning pink or salmon, the keel yellow-tipped; filaments about equal, all dilated at the tip; fr spreading or deflexed, 2–3 cm; 2n=14. Various habitats. May–Sept. Two vars.: Var. purshianus, usually pubescent, and with the lfls mostly 2–3.5 times as long as wide, occurs from the Pacific states and adj. Can. and Mex., e. to w. Minn., w. Mo., and Tex., and is occasionally adventive farther e. (Hosackia americana) Var. helleri (Britton) Isely, usually glabrate or only slightly pubescent, and with the lfls mostly 4–5 times as long as wide, occurs in a disjunct area on the piedmont from s. Va. to n. Ga. (L. helleri; Hosackia h.; Acmispon h.)