LEGUMINOS#. SILVA OF NORTH AMERICA. 30 
DALEA SPINOSA. 
FLowers loosely racemose ; calyx 10-ribbed, conspicuously glandular; petals 
adnate to the staminal tube by their bases only. Legume exserted from the calyx 
for half its length; ovules 4 to 6. 
Dalea spinosa, Gray, Mem. Am. Acad. n. ser. v. 315 (Pl. Bot. Biol. Am. Cent. i. 247: — Sargent, Forest Trees N. 
Thurber.) ; Ives’ Rep. 10. — Torrey, Pacific R. R. Rep. Am. 10th Census U. S. ix. 55.— Brandegee, Proc. Cal. 
iv. 78; vii. pt. ili. 9, t. 3; Bot. Mex. Bound. Surv. 53. — Acad. ser. 2, ii. 148 (Pl. Baja Cal.). 
Walpers, Ann. iv. 485.— Watson, Proc. Am. Acad. xi. Asagreea spinosa, Baillon, Adansonia, ix. 232; Hist. Pl. 
132.— Brewer & Watson, Bot. Cal. i. 143.— Hemsley, ii. 288. 
A small spinose tree, occasionally eighteen or twenty feet high, with a short stout contorted trunk 
sometimes twenty inches in diameter and divided near the ground into several upright branches; or 
more often a low rigid intricately branched shrub. The bark of the trunk is dark gray-brown, nearly 
a quarter of an inch thick, deeply furrowed, and roughened on the surface with small persistent scales. 
The branchlets are reduced to slender sharp spines coated with fine hoary pubescence, bearing minute 
nearly triangular scarious caducous bracts, and marked by occasional glandular fistules. These ultimate 
branchlets are developed from stouter ones also covered when young with hoary pubescence, but 
glabrous in their third year, with pale brown bark roughened with lenticels which as it exfoliates shows 
a pale green inner bark. The leaves are few and irregularly scattered near the base of the spinose 
branchlets ; they are cuneate or linear-oblong, sessile or nearly so, and marked by a few large glands, 
especially on the margins, which are entire, wavy, or, on vigorous young shoots or seedling plants, 
remotely and coarsely serrate ; they are hoary-pubescent, three quarters of an inch to an inch in length, 
and an eighth of an inch to half an inch in width, with a broad midrib and three pairs of lateral ribs, 
and are very deciduous, remaining only for a few weeks on the branches. The stipules are minute, 
ovate, and acute, and resemble the leaves and branchlets in their pubescent covering. The flowers are 
produced in June in racemes an inch or an inch and a half long, with slender spinescent hoary-pubescent 
rachises ; they are nearly half an inch long and are borne on short pedicels developed from the axils of 
minute bracts. The calyx-tube is ten-ribbed and marked with about five glands between the dorsal 
ribs ; the lobes are short, ovate, rounded or more or less ciliate on the margins, and reflexed at maturity. 
The petals are dark violet-blue; the standard is cordate, reflexed, and furnished at the base of the 
blade with two conspicuous glands; the wings and keel are attached to the staminal tube by their bases 
only and are almost equal in size, rounded at the apex, and more or less irregular at the base by a deep 
lobe. The ovary, which is pubescent and glandular-punctate, develops into a one-seeded pubescent 
ovate compressed pod twice as long as the calyx and tipped with the remnants of the recurved style. 
The seed is reniform and an eighth of an inch long, with a lustrous pale brown coat irregularly marked 
with darker spots. 
Dalea spinosa inhabits the Colorado Desert of California, where it occurs at Agua Caliente, Toras, 
and in a few other localities, and extends eastward to the valley of the lower Gila River in Arizona and 
the adjacent parts of Sonora, and to Calamujuet in Lower California.’ 
The wood of Dalea spinosa is light, soft, and rather coarse-grained, with many evenly distributed 
open ducts and numerous thin medullary rays. It is walnut-brown in color, with nearly white sapwood 
composed of twelve to fifteen layers of annual growth. The specific gravity of the absolutely dry 
wood is 0.5536, a cubic foot weighing 34.50 pounds. 
1 Where it was collected by T. S. Brandegee. 
