A genus of shrubs exclusively native of N. America, with alternate pinnate leaves and elongated racemes of blue, purple, or white flowers. These plants belong to the pea-flowered group of Leguminosae, but the flowers, instead of having the normal five petals (namely, the standard petal, the two wing petals, and the two forming the keel), have but one – the standard. The flowers, however, are so crowded that the others are not missed. The two dwarf species – canescens and nana – are best adapted for gardens, although the foliage of A. fruticosa is very handsome. The two former can be increased by cuttings when seeds are not available, and A. fruticosa produces sucker growths from the base which can be removed with some roots attached. Besides the species more fully described below, there are in cultivation A. californica Torr. & Gr. (California) and A. virgata Small (S.E. United States). Both resemble A. fruticosa in habit and general aspect, but A. californica has downy stems and leaf-stalks set with prickly glands, whilst A. virgata has broad leathery leaflets and twiggy branches.