R. HISPIDA.—Rose Acacia. North America, 1743. Amongst large-growing shrubs this is certainly one of the most distinct and handsome, and at the same time one of the hardiest and readiest of culture. Under favourable conditions it grows about 16 feet high, with large oval or oblong leaflets, and having the young branches densely clothed with bristles. The flowers, which are individually larger than those of the False Acacia, are of a beautiful rosy-pink, and produced in June and July. It is a very ornamental, small growing species, and one that is peculiarly suitable for planting where space is limited. R. hispida macrophylla (Large-leaved Rose Acacia) is rendered distinct by its generally more robust growth, and by its larger foliage and flowers. The species, however, varies a good deal in respect of the size of leaves and flowers.
R. PSEUD-ACACIA.—Common Locust, Bastard Acacia, or False Acacia. North America, 1640. A noble-growing and handsome tree, with smooth shoots, and stipules that become transformed into sharp, stiff spines. The flowers are in long racemes, pure-white or slightly tinged with pink, and with a faint pleasing odour. This species has been sub-divided into a great number of varieties, some of which are very distinct, but the majority are not sufficiently so to warrant special attention. The following include the best and most popular kinds:—R. Pseud-Acacia Decaisneana, a distinct form bearing light pinky flowers; R. Pseud-Acacia Bessoniana, with thornless branches and a dense head of refreshing Pea-green foliage; R. Pseud-Acacia angustifolia, with narrow leaves; R. Pseud-Acacia aurea, a conspicuous but not very constant golden leaved form; R. Pseud-Acacia inermis, of which there are weeping, upright, and broad-leaved forms, has narrow leaves that are glaucous beneath, and the characteristic spines of the species are wanting or rarely well developed. R. Pseud-Acacia monophylla is very distinct, the leaves being entire instead of pinnate; while R. Pseud-Acacia crispa has curiously-curled foliage. Then there is the peculiar R. Pseud-Acacia tortuosa, of ungainly habit; R. Pseud-Acacia umbraculifera, with a spreading head; R. Pseud-Acacia sophoraefolia, the leaves of which resemble those of Sophora japonica; and R. Pseud-Acacia amorphaefolia, with very large foliage when compared with the parent tree. The above may be taken as the most distinct and desirable forms of the False Acacia, but there are many others, such as R. Pseud-Acacia colutoides, R. Pseud-Acacia semperflorens, and R. Pseud-Acacia Rhederi, all more or less distinct from the typical tree.
R. VISCOSA (syn R. glutinosa).—Clammy Locust. North America, 1797. This is a small-growing tree, and readily distinguished by the clammy bark of the younger shoots. Flowers in short racemes, and of a beautiful rose-pink, but varying a good deal in depth of tint. It is a valuable species for ornamental planting, and flowers well even in a young state.