LEGUMINOSZ. SILVA OF NORTH AMERICA. oO” 
ROBINIA. 
FLOWERS in drooping axillary racemes; calyx 5-lobed, the upper lobes sub- 
connate; standard large, reflexed, barely longer than the wings and keel; ovary 
stipitate, many-ovuled. Legume linear, compressed, 2-valved. Leaves unequally 
pinnate. 
Robinia, Linnezus, Gen. 220. — Adanson, Fam. PI. ii. 323. — 273. — Endlicher, Gen. 1274. — Meisner, G'en. 89. — Ben- 
A. L. de Jussieu, Gen. 358. — De Candolle, Mém. Légum. tham & Hooker, Gen. i. 499.— Baillon, Hist. Pl. ii. 267. 
Trees or rarely shrubs, spreading by underground shoots, with slender terete or slightly many- 
angled zigzag branchlets of indefinite growth. Buds minute, naked, subpetiolar, three or four 
together, superposed, protected collectively in a depression by a scale-like covering lined on the mner 
surface with a thick coat of tomentum and opening in early spring, its divisions persistent through 
the season on the base of the branchlet developed usually from the upper bud.’ Leaves unequally pin- 
nate, deciduous; leaflets oval, entire, petiolulate, reticulate, penniveined, stipellate; stipules setaceous, 
becoming spinescent at maturity, persistent. Flowers long-pedicellate in short pendulous racemes 
developed from the axils of the leaves of the year. Bracts and bractlets small, acuminate, early 
deciduous. Calyx campanulate, five-toothed, or cut, the upper lobes shorter than the others, cohering 
for a part of their length and valvate in estivation. 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 ample, naked on the inner surface, obcordate, reflexed; wings oblong-falcate, free ; 
keel-petals valvate in estivation, incurved, obtuse, united below. Stamens ten, inserted with the petals, 
diadelphous ; the nine 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 similar, or those opposite the petals sometimes rather smaller, ovate, attached on the back 
near the base, two-celled, the cells opening longitudinally. Ovary linear-oblong, stipitate ; style subu- 
late, inflexed, bearded along the inner side near the apex; stigma terminal, small; ovules suspended 
from the interior angle of the ovary, two-ranked, superposed, amphitropous, the micropyle superior. 
Legume many-seeded, linear-compressed, almost sessile, two-valved, the seed-bearing suture narrow- 
winged ; valves thin and membranaceous. Seed oblong-oblique, transverse, estrophiolate, attached by a 
stout persistent incurved funiculus enlarged at the point of attachment to the placenta; testa thin, 
crustaceous; albumen thin, membranaceous. Embryo large; cotyledons oval, fleshy; radicle short, 
much reflexed, accumbent. 
The genus Robinia is North American. Four species inhabit the territory of the United States ; 
and two, or possibly more, very imperfectly known, occur nm Mexico.” Robinia was once more widely 
distributed over the earth’s surface, and the traces of its presence in the Old World are found in the 
Cretaceous and Eocene rocks of central Europe, where analogues of existing forms abound.*? Of the 
species of our territory three are arborescent and one is shrubby.’ 
1 The subpetiolar buds are often accompanied by a supplemen- 8 Saporta, Origine Paléontologique des Arbres, 312. 
tary supra-axillary bud which sometimes develops late in the season 4 Robinia hispida, Linneus, Mant. 101. — Schmidt, Oestr. Baum. 
into a feeble branchlet which apparently does not survive the first i. 30, t. 31. — Bot. Mag. t. 311.—De Candolle, Prodr. ii. 262. — 
winter. Guimpel, Otto & Hayne, Abbild. Holz. 83, t. 66.— Torrey & Gray, 
2 Schlechtendal, Linnea, xii. 305, 306.— Hemsley, Bot. Biol. Am. Fl. N. Am. i. 295. — Watson & Coulter, Gray’s Man. ed. 6, 134.. 
Cent. i. 259. 
