LEGUMINOSZ. SILVA OF NORTH AMERICA. 85 
CERCIDIUM TORREYANUM. 
Green Barked Acacia. Palo Verde. 
LEGUME somewhat turgid, often slightly contracted between the seeds, the nerve 
of the ventral suture often slightly grooved. Leaflets glaucous. 
Cercidium Torreyanum, Sargent, Garden and Forest, ii. Parkinsonia Torreyana, Watson, Proc. Am. Acad. xi. 
388. 135.— Brewer & Watson, Bot. Cal. i. 162. — Hemsley, 
Cercidium floridum, Torrey, Pacific R. R. Rep. iv. 82; Bot. Biol. Am. Cent. i. 327. 
v. 360, t.3; Bot. Mex. Bound, Surv. 59 (not Bentham). — 
Gray, Ives’ Rep. 11. 
A low, intricately branched tree, leafless for most of the year, twenty-five to thirty feet in height, 
with a short often inclining trunk eighteen or twenty inches in diameter, and stout branches covered 
with yellow or olive-green bark, forming a narrow upright irregular head. The bark of the trunk on 
old trees is reddish brown, an eighth of an inch thick, and furrowed near the base, the surface sepa- 
rating into thick plate-like scales; on young individuals it is thinner, smooth, and pale olive-green. 
The branchlets are slightly zigzag, quite glabrous even when they first appear, light yellow or pale 
olive-green and glaucous, and are armed with thin straight or curved spines a quarter of an inch long. 
The leaves are an inch in length, covered when they unfold with pale tomentum, and puberulous 
at maturity, with slender petioles and two pinne, each composed of two or three pairs of oblong 
obtuse glaucous leaflets narrowed towards the somewhat oblique base, and from a twelfth to a sixth 
of an inch long. The leaves, which are few and scattered, unfold in March and April, and fall almost 
as soon as they are fully grown, a small second crop sometimes appearing in September after the autumn 
rains. The flowers, which open in April, are hardly distinguishable from those of Cercidium floridum. 
The legumes are three or four inches long, two to eight-seeded, slightly turgid, and often contracted 
between the seeds, the nerve of the ventral suture being often grooved ; they ripen and fall from the 
trees during the month of July. The seeds are thicker, but otherwise resemble those of Cercidium 
floridum. 
Cercidium Torreyanum grows on the Colorado Desert of southern California and in the valley 
of the lower Gila River in Arizona, extending southward into Sonora and Lower California.’ It is 
scattered on the sides of low canons and in depressions among the sand-hills of the desert, which it 
brightens with the cheerful coloring of its trunk and branches, exciting the delight and wonder of 
all travelers in that dreary and forbidding region. 
The wood of Cercidium Torreyanum is heavy although not strong, soft and close-grained, with 
a satiny surface susceptible of receiving a good polish. It contains numerous thin medullary rays, and 
small evenly distributed open ducts. It is light brown with clear light yellow sapwood. The specific 
gravity of the absolutely dry wood is 0.6531, a cubic foot weighing 40.70 pounds. 
The Green-barked Acacia was probably discovered in southern California by Frémont during his 
second transcontinental journey. 
1 Vasey & Rose, Contrib. U. S. Nat. Herb. No. 3, 69, 88. 
