in botany, a genus of the diadelphia dianthid clas of plants, the corolla of which is papilionaceous; the vexillum is roundish, large, emarginated, and wholly reflected; the fruit is a large, acuminate, oblong pod, composed of two valves, and containing two cells; the seeds are numerous, elliptical, and frequently compressed. There are twenty-five species, none of them natives of Britain.