Genus 31. ROBÍNIA.
Trees or shrubs with alternate, odd-pinnate leaves, having spines on each side of the stalk in place of stipules. Leafstalk thickened near the base, and covering 2 to 3 buds for the growth of a branch for the next year. An axillary bud also found that may produce a branch the same year as the leaf. Flowers large, pea-blossom-shaped, in large clusters. Fruit a pea-shaped pod.
| * Branchlets and leafstalks not sticky | 1. |
| * Branchlets and leafstalks sticky | 2. |
R. Pseudacácia.
1. Robínia Pseudacácia, L. (Common Locust.) Leaflets 9 to 19, small, oblong-ovate, entire, thin. Twigs purplish-brown, slender, smooth, not sticky. Flowers white, fragrant, in hanging racemes, 3 to 6 in. long. June. Pods flat, smooth, purplish-brown, ripe in September. An irregularly growing, slender tree, 70 to 80 ft. high, with white or greenish-yellow, very durable wood, and on old trees very rough bark with long, deep furrows. Native; Pennsylvania, west and south, and extensively planted and naturalized throughout. A number of varieties, some of which are thornless, are in cultivation.
R. viscòsa.
2. Robínia viscòsa, Vent. (Clammy Locust.) Leaflets 11 to 25, ovate-oblong, sometimes slightly heart-shaped at base, tipped with a short bristle. Twigs and leafstalks sticky to the touch. Flowers in a short, rather compact, upright raceme, rose-colored and inodorous. A small tree, 30 to 40 ft. high; native south, and has been quite extensively cultivated north.
3. Robínia híspida, L. (Bristly Locust. Rose-acacia.), with bristly leafstalks and branchlets, and large rose-colored flowers, is only a bush. Often cultivated. Wild from Virginia and south.