572 TREES OF NORTH AMERICA 



covering lined on the inner surface with a thick coat of tomentum and opening in 

 early spring, its divisions persistent during the season on the base of the branchlet 

 developed usually from the upper bud. Leaves unequally pinnate, petiolate, decid- 

 uous; leaflets entire, penniveined, stipellate, reticulate- venulose, petiolulate; stipules 

 setaceous, becoming spinescent at maturity, persistent. Flowers on long pedicels, in 

 short pendulous racemes from the axils of leaves of the year, with small acuminate 

 caducous bracts and bractlets; calyx campanulate, 5-toothed or cut, the upper lobes 

 shorter than the others, cohering for part of their length; corolla papilionaceous, 

 petals shortly unguiculate, inserted on a tubular disk glandular on the inner surface 

 and connate with the base of the calyx-tube; standard large, reflexed, barely longer 

 than the wings and keel, naked on the inner surface, obcordate, reflexed; wings 

 oblong-falcate, free; keel-petals incurved, obtuse, united below; stamens 10, in- 

 serted with the petals, the 9 inferior united into a tube often enlarged at the base 

 and cleft on the upper side, the superior one free at the base and connate in the 

 middle with the staminal tube, or finally free; anthers ovate; ovary inserted at the 

 base of the calyx, linear-oblong, stipitate; style subulate, inflexed, bearded along 

 the inner side near the apex, with a small terminal stigma; ovules numerous, sus- 

 pended from the inner angle of the ovary, in two ranks, superposed. Legumes in 

 drooping many-fruited racemes, many-seeded, linear-compressed, almost sessile, 

 2-valved, the seed-bearing suture narrow-winged; valves thin and membranaceous. 

 Seed oblong-oblique, transverse, attached by a stout persistent incurved funicle 

 enlarged at the point of the attachment to the placenta; seed-coat thin, crusta- 

 ceous; albumen thin, membranaceous; cotyledons oval, fleshy; radicle short, much 

 reflexed, accumbent. 



Robinia with seven or eight species is confined to the United States and Mexico; 

 of the three or four species found in the United States three are arborescent. 



The generic name commemorates the botanical labors of Jean and Vespasien 

 Robin, arborists and herbalists of the king of France in the sixteenth and seven- 

 teenth centuries. 



CONSPECTUS OF THE ARBORESCENT SPECIES OF THE UNITED STATES. 



Legume without glandular hairs ; flowers white. 1. R. Pseudacacia (A, C). 

 Legume glandular-hispid ; flowers rose color. 



Glands not viscid. 2. R. Neo-Mexicana (F, H). 



Glands exuding a clammy sticky substance. 3. R. viscosa (A). 



1. Robinia Pseudacacia, L. Locust. Acacia. Yellow Locust. 



Leaves 8'-14' long, with slender puberulous petioles, and 7-9 leaflets, turning pale 

 clear yellow late in the autumn just before falling; stipules \' long, linear, subulate, 

 membranaceous, at first pubescent and tipped with small tufts of caducous brown 

 hairs, becoming straight or slightly recurved spines persistent for many years and 

 ultimately often more than 1' long; leaflets oval, rounded or slightly truncate and 

 minutely apiculate at the apex, when they unfold covered with caducous silvery 

 pubescence, at maturity very thin, dull dark blue-green above, pale below, glabrous 

 with the exception of the slight pubescence on the under side of the slender midribs, 

 l^'-2' long and '-f wide; their petiolules stout, \'-\' long; stipels minute, linear, 

 membranaceous, early deciduous. Flowers opening late in May or early in June, 

 filled with nectar, very fragrant, on slender pedicels ^' long, and dark red or red 



