LEGUMINOSE. SILVA OF NORTH AMERICA. 99 
PROSOPIS. 
FLowers perfect, regular, in axillary cylindrical spikes or globose heads; calyx 
campanulate, 5-toothed, the teeth valvate in estivation ; petals 5, valvate in estivation ; 
stamens 10, free; ovary sessile or stipitate, many-ovuled. Legume linear, compressed 
or subterete, indehiscent. Leaves bipinnate. 
Prosopis, Linneus, Mant. 10.— Meisner, Gen. 96.— End- Algarobia, Bentham, Pl. Hartweg. 13.— Torrey & Gray, 
licher, Gen. 1324. — Bentham & Hooker, Gen. i. 591. — Fl. N. Am. i. 399. — Endlicher, Gen. 1324. 
Baillon, Hist. Pl. ii. 64. 
Trees or shrubs, with aculeate or naked branches sometimes armed with solitary or geminate 
axillary spines or spinescent stipules. Leaves bipinnate with two to four or rarely many pinne, the 
pinne many or few-foliolate ; petioles and petiolules usually furnished with minute or obscure glands ; 
leaflets often rigid ; stipules minute or wanting. Flowers usually sessile, in axillary spikes or heads. 
Calyx five-toothed or slightly five-lobed, deciduous. Petals connate below the middle or ultimately 
free, glabrous or tomentose on the inner surface towards the apex, sometimes puberulous on the outer 
surface, hypogynous. Stamens ten, free, inserted with the petals on the margin of a minute obscure 
disk adnate to the calyx-tube, those opposite the lobes of the calyx rather longer than the others; 
filaments filiform; anthers oblong, attached on the back below the middle, versatile, introrse, two- 
5? 
celled, the connective tipped with a minute deciduous gland or rarely eglandular, the cells opening 
longitudinally by marginal sutures. Ovary inserted in the base of the calyx, sessile or stipitate, villose 
or glabrous, many-ovuled ; style filiform, tipped with a minute stigma; ovules suspended in two ranks 
from the inner angle of the ovary, superposed, anatropous, the micropyle superior. Legume linear, 
compressed or subterete, straight, faleate, contorted or twisted into a more or less regular spiral, inde- 
hiscent ; exocarp thin or coriaceous; mesocarp thick, spongy, or hardened, rarely thin; endocarp 
cartilaginous or papery, inclosing the seeds individually in distinct nutlke joints, or occasionally con- 
tinuous and scarcely distinguishable from the mesocarp. Seed ovate or oblong, compressed, the hilum 
near the base; testa crustaceous. Embryo surrounded by a layer of horny albumen ; cotyledons flat, 
the radicle short, straight, slightly exserted. 
The genus Prosopis is distributed from the southern borders of the United States to Patagonia, 
and occurs in tropical Africa, in the Orient, and in tropical and subtropical Asia. Sixteen or seventeen 
species are distinguished,’ three of which belong to the Old World. The type of the genus, P. spici- 
gera,’ is found from Persia and Afghanistan to southern India, where in arid regions it sometimes forms 
extensive forests. Prosopis Stephaniana® inhabits Cyprus, the Caucasus, Persia, and Afghanistan, 
extending eastward as far as the Punjab, and Prosopis oblonga* Upper Guinea and the Nile-land. 
Two of the species found within the territory of the United States are small trees, and the third, Proso- 
pis cinerascens,® a native of the valley of the lower Rio Grande, is a low shrub. The other American 
species are shrubs of Mexico and Peru, and the extratropical countries south of the equator. 
1 Bentham, Trans. Linn. Soc. xxx. 376 (Rev. Mim.). — Watson, 4 Bentham, Hooker Jour. Bot. iv. 348; Trans. Linn. Soc. l. c. 
Proc. Am. Acad. xxiv. 48. — Brandegee, Proc. Cal. Acad. ser. 2, 377. — Oliver, Fl. Trop. Afr. ii. 331. 
ii. 152 (Pl. Baja Cal.). 5 Bentham, 1. c. 381. — Coulter, Contrib. U. S. Nat. Herb. ii. 95 
2 Linneus, Mant. 68.— De Candolle, Prodr. ii. 446.— Boissier, (A/an. Pl. W. Texas). 
FI. Orient. ii. 634. — Bentham, I. c. — Hooker f. Fl. Brit. Ind. ii. 288. Strombocarpa cinerascens, Gray, Smithsonian Contrib. iii. 61 (Pl. 
8 Kunth, Steudel Nom. Bot. ii. 399.— Boissier, J. c.633.— Ben- Wright. i.). — Walpers, Ann. iv. 614. — Torrey, Bot. Mex. Bound. 
tham, /. c. — Hooker f. /. c. Surv. 60. 
