LEGUMINOS &. SILVA OF NORTH AMERICA. 19 
ACACIA TORTUOSA. 
FLowers in globose heads on elongated peduncles. Legume slender, elongated, 
puberulous. Branches armed with persistent spinescent stipules. 
Acacia tortuosa, Willdenow, Spec. iv. 1083 (1805). — De Am. Cent. i. 355.— Coulter, Contrib. U. S. Nat. Herb. 
Candolle, Prodr. ii. 461.— Sprengel, Syst. iii. 144. — ii. 99 (Man. Pl. W. Texas). 
Bentham, Lond. Jour. Bot. i. 392 ; Trans. Linn. Soc. xxx. Mimosa tortuosa, Linnzus, Spec. ed. 2, 1505 (1768). 
501 (Rev. Mim.).— Torrey, Bot. Mex. Bound. Surv.62.— Acacia leucacantha, Sprengel, Syst. iii. 144 (1826). 
Grisebach, Fl. Brit. W. Ind. 222.— Hemsley, Bot. Biol. Acacia albida, Lindley, Bot. Reg. xvi. t. 1317 (not Delile) 
(1830). 
Usually shrubby in Texas, with numerous stems forming a symmetrical round-topped bush only 
a few feet high, Acacia tortuosa on the plain of the Rio Grande near Spofford occasionally becomes 
arborescent in habit and, reaching a height of from fifteen to twenty feet, forms a straight stem five or 
six inches in diameter covered with dark deeply furrowed bark and surmounted by an open irregular 
head of stout wide-spreading branches. The branchlets are slender, somewhat zigzag, slightly angled, 
roughened by numerous minute round lenticels, reddish brown, villose, with short pale hairs, and armed 
with thin terete puberulous spines developed from the persistent stipules and occasionally three 
quarters of an inch long. The leaves are alternate on the young branchlets and are fascicled from 
earlier axils; they are generally less than an inch in length, short-petiolate, with slender puberulous 
rachises and with usually three or four pairs of pinne, and are early deciduous ; the pinne are sessile 
or short-stalked and remote, with from ten to fifteen pairs of leaflets. These are linear, somewhat 
falcate, acute, tipped with minute points, subsessile, light green, glabrous, and from one twentieth to one 
sixteenth of an inch in length. The peduncles appear in March with or just before the unfolding of 
the leaves and are axillary, solitary or usually clustered, slender, puberulous, from one half to three 
quarters of an inch in length, and furnished at the apex with two minute connate bracts. Before the 
flowers open the flower-heads are glabrous, and after the flowers open they are from one quarter to 
three eighths of an inch in diameter. The flowers are bright yellow and very fragrant, and are 
produced from the axils of minute clavate pilose bractlets. The calyx is only about one third as long 
as the corolla, with short lobes puberulous like those of the corolla, which is less than half as long 
as the filaments. The ovary is nearly sessile and covered with short close pubescence. The legumes 
are indehiscent, elongated, linear, slightly compressed, somewhat constricted between the numerous 
seeds, from three to five inches long and about a quarter of an inch wide, dark red-brown, and 
cinereo-puberulous. The seeds are in one series, obovate, compressed, dark red-brown, lustrous, and 
about a quarter of an inch long; their coat is crustaceous, with a thin testa and a thicker pale 
and harder tegmen. The embryo is pale yellow, with thick cotyledons and a short slightly exserted 
radicle. 
In Texas Acacia tortuosa is distributed from the valley of the Rio Cibolo to Eagle Pass on the 
Rio Grande. What is considered the same species is common in northern and southern Mexico, the 
West Indies, Venezuela, and on the Galapagos Islands.’ 
Acacia tortuosa was collected by Lindheimer on the Rio Cibolo in 1850. It had been 
previously collected by Berlandier in 1843 in Tamaulipas, probably in the Rio Grande valley, and it 
1 I have followed Bentham and Gray in considering this western the adjacent parts of Mexico appears to be so restricted, it is not 
Texas Acacia identical with the West Indian, Mexican, tropical improbable that a better knowledge than is now available of the 
American, and Galapagos species, but as its range in Texas and in tropical American species will show it to be distinct. 
