A shrub 3 to 6 ft high with numerous interlacing, angular, grey stems, armed with stout axillary simple or branched spines. Leaves simple, linear-lanceolate, 1⁄8 to 7⁄16 in. long, 1⁄16 to 1⁄12 in. wide, slightly hairy beneath; petioles with a pair of short spines near the apex. Flowers yellow, produced in early summer in axillary clusters on the upper part of the stems and along the spines. Lips of calyx equal, shorter than the tube. Standard glabrous, 5⁄16 to 1⁄2 in. long; keel glabrous, slightly shorter than the standard. Pods linear-oblong, containing three to seven brownish-green seeds.
Native of southern France and Spain (the same or a very closely related species in Corsica and Sardinia), inhabiting dry places; although Aiton, citing Lobel as his authority, gives 1570 as the earliest known date of cultivation in Britain, it is probable that it was not introduced until the late 18th or early 19th century. It is an interesting strongly armed shrub, almost leafless by midsummer.