Distribution. Dry rocky slopes and mesas, usually at altitudes between 6000° and 8000°; northern Utah and central Nevada, through Arizona and western New Mexico to northern Mexico; common and probably of its largest size near the southern rim of the Grand Cañon, and on the lower slopes of the San Francisco Mountains, Arizona.
9. CERCOCARPUS H. B. K. Mountain Mahogany.
Trees or shrubs, with scaly bark, rigid terete branches, short lateral spur-like branchlets conspicuously roughened for many years by the crowded narrow horizontal scars of fallen leaves, minute buds, the scales of the inner rows accrescent on the growing shoots and often colored. Leaves alternate, simple, entire or serrate, coriaceous, straight-veined, short-petiolate, persistent; stipules minute, adnate to the base of the petiole, deciduous. Flowers axillary on the short lateral branchlets, sessile or short-pedicellate, solitary or fascicled, the pedicels sometimes lengthening before the fruit ripens; calyx-tube long, cylindric, abruptly expanded at apex into a cup-shaped, 5-lobed deciduous limb, the lobes imbricated in the bud; disk thin, slightly glandular, adnate to the tube of the calyx; petals 0; stamens 15—30, in 2 or 3 rows; filaments incurved in the bud, free, short, terete; anthers oblong, pubescent or tomentose, distinct and united by a broad connective; ovary composed of a single carpel inserted in the bottom and included in the tube of the calyx, acute, terete, smooth, striate or sulcate, sericeous, rarely bicarpellate; style terminal, filiform, villose or glabrate, crowned with a minute obtuse stigma; ovule solitary, subbasilar, ascending; raphe dorsal; micropyle inferior. Fruit a linear-oblong coriaceous slightly ridged angled or sulcate akene, included in the persistent tube of the spindle-shaped calyx more or less deeply cleft at the apex, and tipped with the elongated persistent style clothed with long white hairs. Seed solitary, linear, acute, erect; hilum conspicuous lateral above the oblique base; testa membranaceous; embryo filling the cavity of the seed; cotyledons ovate-oblong, elongated, fleshy; radicle inferior.
Cercocarpus is confined to the dry interior and mountainous regions of North America. Twenty-one species, often of doubtful value, have been distinguished; seventeen are credited to the territory of the United States and the others to Mexico. The heavy hard brittle wood of all the species makes valuable fuel and is occasionally used in the manufacture of small articles for domestic and industrial use.
The generic name, from κέρκος and καρπός, refers to the peculiar long-tailed fruit.
CONSPECTUS OF THE ARBORESCENT SPECIES OF THE UNITED STATES.
Flowers usually in many-flowered clusters. Leaves coarsely serrate above the middle. Leaves oval to semiorbicular or obovate, hoary-tomentose below, sinuate-dentate; flowers short-pedicellate.1. [C. Traskiæ.] Leaves oval to slightly obovate, green and glabrous below, denticulate with broad apiculate teeth; flowers long-pedicellate.2. [C. alnifolius.] Leaves finely serrate above the middle, obovate to oval, pale and villose below; flowers short-pedicellate.3. [C. betuloides.] Flowers solitary or rarely in 2 or 3-flowered clusters, nearly sessile. Leaves narrow-lanceolate, lance-elliptic or oblanceolate, acute at the ends, entire, pale or rufous below.4. [C. ledifolius.] Leaves oblong-obovate to narrow-elliptic, entire or slightly dentate below the apex, villose-pubescent.5. [C. paucidentatus.]
1. [Cercocarpus Traskiæ] Eastw.
Leaves oval to semiorbicular or obovate, rounded or acute at apex, cuneate, rounded or occasionally somewhat cordate at the narrow base, revolute on the margins, entire below, coarsely sinuate-dentate above the middle with slender teeth tipped with minute dark glands, when they unfold covered above with soft pale hairs and below with thick hoary tomentum, and at maturity coriaceous, dark green, lustrous and villose or nearly glabrous on the upper surface, pale-tomentose on the lower surface, 1½′—2′ long, and 1′—1½′ wide, with prominent primary veins running obliquely to the point of the teeth, and, like the stout midrib, conspicuously impressed on the upper side; petioles stout, hoary-tomentose, about ¼′ in length; stipules acuminate, scarious, covered on the margins with long white hairs, ¼′ long. Flowers appearing early in March, nearly sessile, in 1—5 usually 4 or 5-flowered clusters, hoary-tomentose, ½′—¾′ long; calyx broad, glabrous on the inner surface; anthers tomentose. Fruit: mature calyx, light reddish brown, villose-pubescent, deeply cleft at apex, ½′ long; akene slightly ridged on the back, ⅓′ in length, covered with long lustrous white hairs; style 1½′—2′ in length.