Leaves elliptic, ovate or rarely slightly obovate, acute, rounded or occasionally acuminate or abruptly narrowed into a short obtuse point at apex, rounded or broad-cuneate at base, finely crenately serrate, glabrous, light green and lustrous on the upper surface, lighter green and glabrous on the lower surface, 1½′—2′ long and ¾′—1′ wide, with a slender midrib, thin veins and reticulate veinlets; petioles slender, glabrous or rarely slightly villose, without glands, ¼′—½′ in length. Flowers appearing when the leaves are nearly fully grown from the first to the middle of May, ¼′ in diameter, on slender glabrous pedicels, in erect or spreading many-flowered glabrous or puberulous racemes 3′—6′ long; calyx-tube saucer-shaped, glabrous, 3/16′ wide, persistent under the fruit, the lobes short-pointed, acute, persistent; petals broad-obovate, pure white. Fruit ripening in August and September, in erect or spreading racemes, subglobose to short-oblong, purplish black and lustrous at maturity, ¼′—½′ in diameter, with thin juicy acrid flesh; stone compressed, slightly obovoid ¼′ in diameter, with a low broad ridge on the ventral suture, and rounded on the dorsal suture.
A tree in sheltered cañons sometimes 25°—30° high, with a trunk 18′ or 20′ in diameter, small, usually drooping or occasionally wide-spreading branches, and slender glabrous red-brown pendulous branchlets marked by small pale lenticels, becoming gray-brown in their second year; on open mountain slopes a shrub with numerous erect stems and usually smaller leaves. Winter-buds acute or acuminate, 1/16′—⅛′ long, with slightly villose red-brown scales. Bark near the base of old trunks ¼′ thick, nearly black, deeply fissured and broken on the surface into thin persistent scales, higher on the trunk and on small stems thin, smooth, reddish or gray-brown, lustrous and marked by many narrow oblong pale horizontal lenticels.
Distribution. Guadalupe Mountains, western Texas, over the mountain ranges of southern New Mexico and Arizona, extending northward in Arizona to the cañons of the Colorado plateau south of the Colorado River; widely and generally distributed at altitudes between 5000° and 8000°, but nowhere abundant. Passing into var. rufula Sarg., differing in the rusty brown pubescence on the lower side of the midrib of the leaves, in the pubescent petiole and lower part of the rachis, in the puberulous ovary, and in the rusty brown pubescence of the young branchlets.
Distribution. With the species on many of the mountain ranges of southern New Mexico and Arizona at altitudes between 5400° and 6000°.
19. [Prunus caroliniana] Ait. Wild Orange. Mock Orange.
Leaves oblong-lanceolate, acuminate, mucronate, with entire thickened slightly revolute margins, or rarely remotely spinulose-serrate, glabrous, coriaceous, dark green and lustrous on the upper surface, paler on the lower surface, 2′—4½′ long and ¾′—1½′ wide, and obscurely veined, with a narrow pale midrib; persistent until their second year; petioles stout, broad, orange-colored; stipules foliaceous, lanceolate, acuminate. Flowers appearing from February to April, on slender pedicels about ½′ long, from the axils of long-acuminate scarious red-tipped bracts, in dense racemes shorter than leaves; calyx-tube narrow-obconic, the lobes small, thin, rounded, undulate on the margins, reflexed after the flowers open, deciduous; petals boat-shaped, minute, cream-colored; stamens exserted, orange-colored, with glabrous filaments and large pale anthers; ovary gradually narrowed into a slender erect style enlarged above into a club-shaped stigma. Fruit ripening in the autumn, remaining on the branches until after the flowering period of the following year, oblong, short-pointed, black and lustrous, ½′ long, with a thick skin, and thin dry flesh; stone short-ovoid, pointed, nearly cylindric, about ½′ long, full and rounded at base, with thin fragile walls, obscurely ridged on the ventral suture and deeply grooved on the dorsal suture.
A tree, 30°—40° high, with a straight or inclining trunk sometimes 10′ in diameter, slender horizontal branches forming a narrow oblong or sometimes a broad head, and glabrous branchlets marked by occasional pale lenticels, slightly angled, at first light green, becoming bright red, and in the second season light brown or gray. Winter-buds acuminate, ⅛′ long, covered with narrow pointed dark chestnut-brown scales rounded on the back. Bark about ⅛′ thick, gray, smooth or slightly roughened by longitudinal fissures, and marked by large irregular dark blotches. Wood heavy, hard, strong, close-grained, light red-brown or sometimes rich dark brown, with thick lighter colored sapwood. The partially withered leaves and young branches are often fatal to animals browsing upon them, owing to the considerable quantities of hydrocyanic acid which they contain.
Distribution. Deep rich moist bottom-lands; valley of the Cape Fear River, North Carolina, to the shores of Bay Biscayne and the valley of the Kissimee River, Florida, and through southern Alabama, Mississippi, and Louisiana to the valley of the Guadalupe River, Texas; in Bermuda; in the Atlantic and eastern Gulf states usually only in the immediate neighborhood of the sea, rarely ranging inland more than fifteen or twenty miles; common along the borders of hummocks in the center of the Florida peninsula and a characteristic tree on those in the region of Lake Apopka, Orange County; in Alabama ranging inland to Dallas County (Pleasant Hill, T. B. Harbison); most abundant and of its largest size in the valleys of eastern Texas, and here often forming great impenetrable thickets.