Crown Vetch (Securigera varia)
Crown Vetch is often planted to control erosion on hillsides; it also escapes freely and makes a nuisance of itself. But the bicolored flowers are pretty.
Gray describes the genus (he places it in Coronilla) and the species:
CORONILLA L. Calyx 5-toothed. Standard orbicular; keel incurved. Stamens diadelphous. 9 and 1. Pod terete or 4-angled, jointed; the joints eubrylindric. — Glabrous herbs or shrubs, with pinnate leaves, and the flowers in umbels terminating axillary peduncles. (Diminutive of corona, a crown, alluding to the inflorescence.)
C. vària L. A perennial herb with ascending stems; leaves sessile; leaf lets 15-25, oblong; flowers rose-color; pods coriaceous, 3-7 -jointed, the 4-angled joints 6-8 mm. long. — Roadsides and waste places, N. E. to N. J. (Nat. from Eu.)