550 



TREES OF NORTH AMERICA 



tomentose below, i'-|' long, tardily deciduous or persistent until spring; leaves on vigorous 

 shoots and on flower-bearing branchlets occasionally linear and entire; stipules ciliate on 

 the margins, united below and adnate to the short persistent petiole, free above the mid- 

 dle and acute at apex, persistent and becoming woody on the flower-bearing branchlets. 

 Flowers appearing in early spring, 1' in diameter; calyx-tube more or less tomentose and 

 covered with rigid glandular hairs, the lobes rounded at apex, hoary-tomentose; petals 

 broad-obovate, rounded and emarginate at apex, cuneate and short-stipitate below, pale 

 yellow or nearly white. Fruit ripening in October, about 1' long and as long as the calyx- 

 tube, the elongated style often 2' in length. 



A tree, occasionally 20-25 high, with a tall trunk 6'-8' in diameter, short spreading 

 branches forming a narrow head, and slender rigid branchlets red and glandular during 



Fig. 506 



their first season, becoming dark reddish brown and glabrous the following year. Bark 

 of the trunk pale gray, separating freely into long narrow thin loosely attached plates; more 

 often a shrub with spreading stems often only a few feet tall. 



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 Canon, 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 



