LEGUMINOS 2, 
SILVA OF NORTH AMERICA. 
15 
PROSOPIS JULIFLORA, var. VELUTINA. 
Mesquite. 
LEAFLETS crowded, cinereo-pubescent. 
Prosopis juliflora, var. velutina. 
Algarobia glandulosa, Torrey, Pacific Rk. R. Rep. vii. 
pt. iii. 10 (not Ann. Lyc. N. Y. ii. 192, t. 2) (an part) 
(1856). 
Prosopis juliflora, Torrey, Bot. Mex. Bound. Surv. 60 (in 
Calyx pubescent. 
part) (not De Candolle) (1859). — Rothrock, Wheeler’s 
Fep. vi. 106 (in part). — Sargent, Silva N. Am. iii. 101 
(in part). 
Prosopis velutina, Wooton, Bull. Torrey Bot. Club, xxv. 
456 (1898). 
Prosopis juliflora was first described from trees growing on the island of Jamaica, where it is 
believed to have been introduced from the mainland before the middle of the eighteenth century. The 
Mesquite of western Texas,’ where it is one of the most conspicuous features of vegetation, appears 
identical with the plant which grows on Jamaica; but eastward and westward the Mesquite diverges 
from the western Texas plant, and its extreme forms, distinct enough when seen locally, are connected 
by intermediate forms which make it difficult to find characters by which these can be satisfactorily 
separated as species. The two extreme forms, however, can be well treated as varieties. 
The first of these varieties is the eastern and California tree, Prosopis juliflora, var. glandulosa? 
This is the common Mesquite of eastern Texas, where it is frequently a round-topped tree, twenty feet 
in height, with a trunk a foot in diameter and long gracefully drooping branches forming a symmetrical 
round-topped head, leaves with distant linear mostly acute glabrous dark green leaflets often two inches 
in length, and a glabrous calyx.? This form ranges westward to about the ninety-eighth meridian, 
northward into southern Kansas,‘ and southward into northern Mexico,’ and with rather shorter and 
more crowded leaflets is common in southern California, extending southward into Lower California.’ 
The second variety, Prosopis juliflora, var. velutina, is a tree found only in the hot semitropical 
1 Prosopis juliflora in western Texas and eastern New Mexico is 
usually a shrub sending up a number of stout stems from enormous 
roots, but occasionally becomes a low tree, with a trunk six or 
eight inches in diameter. The leaves are glabrous, with from 
fifteen to twenty pairs of leaflets; these are crowded or more or less 
remote, linear-oblong, rounded or acute at the apex, and from one 
third to one half of an inch in length. The calyx is glabrous. 
Leaves and a flower-spike of Prosopis juliflora are figured on plate 
exxxvi. f. 27 of this work. 
On specimens collected along the shore of Corpus Christi Bay in 
March, 1894, by A. A. Heller, the leaves, with short and compara- 
tively crowded leaflets, are not. distinguishable from those of the 
western Texas Prosopis juliflora. 
2 Prosopis juliflora, var. glandulosa. 
Prosopis glandulosa, Torrey, Ann. Lyc. N. Y. ii. 192, t. 2 
(1828); Emory’s Rep. 139 (in part). — Don, Gen. Syst. ii. 400. — 
Dietrich, Syn. ii. 1424. — Walpers, Rep. i. 861. — Bentham, 
Hooker Jour. Bot. iv. 348; Lond. Jour. Bot. v. 81. 
Algarobia glandulosa, Torrey & Gray, Fl. N. Am. i. 399 
(1838); Pacific R. R. Rep. ii. 164. — Engelmann & Gray, Jour. 
Bost. Soc. Nat. Hist. v. 242 (Pl. Lindheim. i.).— Engelmann, 
Wislizenus Mem. of a Tour to Northern Mexico (Senate Doc. 
1848, Bot. Appx.), 94. — Gray, Jour. Bost. Soc. Nat. Hist. vi. 181 
(Pl. Lindheim. ii.) ; Smithsonian Contrib. iii. 60; v. 51 (PI. 
Wright. i., ii.); Ives’ Rep. 11.— Torrey, Sitgreaves’ Rep. 158 ; 
Bot. Mex. Bound. Surv. 60 (in part). 
8 The most constant character, perhaps, by which the Texas 
and California Mesquite can be distinguished from the form of 
southern Arizona is in the glabrous calyx, for the leaves of this 
form show great variations ; but on a specimen with typical leaves 
collected by Pope in Texas, without other indication, from the 
Thurber Herbarium and now in the Gray Herbarium, the flowers 
and leaflets are tomentose ; and on specimens collected by N. A. 
Carlton in Oldham County, Texas, in 1891, also with leaves of 
the typical var. glandulosa, the calyx is puberulous. These species 
seem to indicate a transition into the pubescent form of southern 
Arizona. 
4 The Mesquite was first collected in Kansas in 1880 by Mr. E. 
N. Plank. See, also, L. F. Ward, Plant World, i. 48, and C. N. 
Gould, Plant World, iv. 74, 193. 
5 Near Matamoras, Berlandier (No. 2344 equals 914), 1831, and 
Gregg, May 10, 1847 (in Herb. Gray); San Luis Potos{, Palmer, 
1878; Parras, and near Saltillo, Palmer, 1880; Manzanilla, Palmer, 
1890; Monterey, C. K. Dodge, April and May, 1891 (in U. S. Nat. 
Herb.). 
6 The specimens collected by T. S. Brandegee at San Gregoria 
in Lower California, February, 1887, and distributed as Prosopis 
pubescens, probably belong to this form. 
