ROBINIA 



Robinia, Linnaeus, Gen. PL 220 (1737) and Sp. PL 722 (1753); Bentham et Hooker, Gen. PL i. 



499 (1865); Schneider, Laubholzkunde, ii. 79 (1907). 

 Pseudacacia, Moench, Meth. 145 (1794). 



Deciduous trees and shrubs belonging to the division Papilionacese of the order 

 Leguminosae. Leaves unequally pinnate, alternate, stalked : leaflets opposite, rarely 

 sub-opposite or alternate, stipellate, stalked, entire, penninerved. Stipules in pairs, 

 at first setaceous, ultimately either deciduous or developing into persistent spines. 

 No true terminal bud is formed, the tip of the branchlet falling off early in summer 

 and leaving a scar at the apex of the twig. Buds minute, multiple, three to five 

 superposed vertically, not apparent ' in summer and autumn, being concealed by the 

 enlarged base of the petiole ; in winter, embedded in a projection on the branchlet 

 between the stipules, and covered by three scales, which are united together and 

 form the leaf-scar. Usually only the uppermost bud develops the scales, which are 

 very tomentose within, bursting open, and afterwards persisting at the base of the 

 new branchlet during the following season. 



Flowers in pendulous racemes, arising from the axils of the leaves, with long 

 pedicels and caducous bracts and bracteoles. Calyx campanulate, unequally five- 

 toothed. Corolla papilionaceous ; petals with short claws, inserted on a tubular 

 glandular disc, connate with the base of the calyx-tube ; standard large, reflexed, 

 obcordate ; wings oblong, curved, free ; keel-petals incurved, obtuse, united below. 

 Stamens ten, inserted with the petals ; nine inferior united into a tube ; upper stamen 

 free at the base. Ovary stalked ; style subulate^ inflexed, pubescent, ending in a 

 small stigma ; ovules numerous, hanging in two rows from the ventral suture. Pods 

 in pendulous racemes, linear-oblong, compressed ; valves two, thin, membranous ; 

 seed-bearing suture with a narrow wing. Seeds numerous, reniform, oblique, with 

 a persistent incurved stalk. % 



About eight species of Robinia are known, confined to the United States and 

 Mexico. Four, all natives of the United States, occur in cultivation : 



I. Branchlets without glands. 



1. Robinia Pseudacacia, Linnaeus. See p. 1497. 



Branchlets at first slightly pubescent, soon becoming glabrous. Leaflets 



1 Occasionally a supra-axillary bud is formed, visible above the insertion of the leaf; it develops into a short-lived feeble 

 branch. 



I496 



