A tree sometimes 50° high, with a straight trunk occasionally 3°—4° in diameter, or divided at the ground into several large stems, stout branches forming a narrow head, and slender branchlets thickly coated when they first appear with rufous pubescence, becoming red-brown, pubescent or puberulous and marked by many small pale lenticels at the end of their first season and ashy gray the following year.
Distribution. Banks of streams in the cañons of central and southern New Mexico and Arizona, and on Oak Creek near Flagstaff, Arizona on the Colorado plateau (_P. Lowell_).
Leaves 9′—12′ long, with slender pubescent or puberulous petioles and rachis, and 13—23 narrow lanceolate long-pointed usually falcate finely serrate leaflets entire or nearly entire on their incurved margins, cuneate or rounded at base, thin, light green, glabrous or pubescent on the midrib below, 2′—3′ long and ⅓′—⅔′ wide. Flowers: staminate in slender aments, 3′—4′ long, pubescent when they first appear, becoming glabrous; calyx short-stalked, nearly orbicular, light yellow-green, puberulous on the outer surface, 3—5-lobed with rounded lobes, their bracts ovate-lanceolate, coated with hoary tomentum; stamens about 20, with nearly sessile yellow anthers and slightly lobed connectives; pistillate flowers oblong, narrowed at the ends, thickly coated with rufous pubescence; bract and bractlets irregularly divided into a laciniate border rather shorter than the ovate acute calyx-lobes; stigmas green tinged with red, ⅓′ long. Fruit globose or subglobose, tipped with the persistent remnants of the calyx, pubescent or puberulous with rusty hairs, ½′—¾′ in diameter, with a thin husk; nut subglobose to slightly ovoid, sometimes obscurely 4-ridged from the apex nearly to the middle (_J. subrupestris_ Dode), deeply grooved with longitudinal simple or forked grooves, 4-celled at base, 2-celled at apex, thick shelled; seed small and sweet.
A shrubby round-headed tree occasionally 20°—30° high, with a short generally leaning trunk 18′—30′ in diameter, usually branching from near the ground, and slender branchlets coated with pale scurfy pubescence often persistent for two or three years, orange-red and marked by pale lenticels in their first winter and ultimately ashy gray; often a shrub with clustered stems only a few feet high. Winter-buds: terminal, ¼′—½′ long, compressed, narrowed and often oblique at apex, covered with pale tomentum; axillary ⅛′ long, compressed, coated with pale pubescence. Wood heavy, hard, not strong, rich dark brown with thick white sapwood. The beauty of the veneers obtained from the stumps of the large trees is fast causing their destruction.