This section is from the book "Handbook Of Hardy Trees, Shrubs, And Herbaceous Plants", by W. Botting Hemsley. Also available from Amazon: Handbook of hardy trees, shrubs, and herbaceous plants.
Trees or shrubs. Leaves abruptly pinnate, often fascicled, the rachis usually terminated by a bristle or rigid prickle. Stipules often spinescent. Flowers yellow, rarely white or red; peduncles 1-flowered, seldom 2- or 3-flowered, fascicled on the old nodes or axillary. Calyx gibbous above. Pod linear, ultimately terete or turgid. About fifteen species, all Asiatic. Karagan is the name G. arborescens bears amongst the Mogul Tartars. The species are very hardy.
1. C. arborescens. - A shrub or small tree. Leaves composed of 8 to 10 oblong mucronate leaflets; common petiole deciduous, stipules scarcely spinescent. Flowers pale or bright yellow according to the variety, appearing in early Spring. A very desirable shrub on account of its extreme hardines: C. sophoraefolia is a form of this with smaller membranous leaves. A native of Siberia.
2. C. Altagana, syn. C. microphylla. - of smaller stature than the foregoing, with smaller more numerous leaflets clothed with appressed hairs, and thorny stipules. The flowers, rather larger, are usually solitary. Also from Siberia, and flowering in Spring.
3. C. Chamlagu. - A dwarf spreading shrub. Leaflets glabrous, mucronulate, in two distant pairs, the upper larger; stipules mostly spinescent. Flowers solitary, dirty yellow, ultimately assuming a reddish tinge, appearing in June. A native of North China, where it bears the specific name.
4. C, frutescens. - Near the last, but of more ancient cultivation. It is of erect habit, with two pairs of contiguous equal leaflets. Flowers solitary, yellow, on jointed peduncles. There are varieties under the names angustifolia, latifolia, etc, in cultivation. A native of Siberia, flowering in May.
There is another group of species in which the common petiole is persistent and thorny. C. triflora and G. pygmaea are the species usually seen. The former has 6 or more pairs of leaflets and 2 or 3 flowers on a common peduncle; and the latter solitary flowers and 2 pairs of leaflets.