A low, decumbent, deciduous shrub 4 or 5 in. high, with round, shallowly grooved, hairy branches. Leaves trifoliolate, with a main-stalk 1⁄4 in. long; leaflets obovate or oblong, 1⁄3 in. long, almost shaggy when young on both sides. Flowers golden yellow, produced in April and May, one to three (occasionally up to six) at each joint, on short hairy stalks, on the terminal part of the previous year’s shoots. Each flower is about 1⁄2 in. long, with a short hairy calyx; the standard petal is orbicular and incurved at the edges. Pod 3⁄4 to 1 in. long, hairy, containing one or two seeds.
Native of the Maritime Alps, where, according to Moggridge (Flora of Mentone, t. 58), it is extremely rare in a wild state owing to the plants being eaten over by grazing animals before the seeds have time to ripen. It was first discovered by Ardoino, after whom it is named, in 1847, but was apparently lost sight of until 1866, when it was found again by the Rev. Wm. Hawker and introduced to cultivation. It is a singularly pretty little shrub, one of the dwarfest of brooms, quite hardy, and flowers freely. Under cultivation it hybridises readily through insect agency if grown near other species. It is the seed parent of C. × kewensis and C. × beanii, as well as some other inferior unnamed kinds. It is a delightful rock garden plant, but if associated with other brooms should he raised from cuttings to be sure of coming true.