7. [Prunus mexicana] S. Wats. Big Tree Plum.
Prunus arkansana Sarg.
Leaves ovate to elliptic or obovate, abruptly long-pointed and acuminate at apex, rounded or rarely cuneate and often glandular at base, and finely doubly serrate with apiculate slender straight or slightly incurved teeth, at maturity thick, dark yellow-green, glabrous and lustrous on the upper surface, paler and sparingly covered on the lower surface with long soft white hairs most abundant on the prominent midrib and primary veins and on the numerous conspicuous reticulate veinlets, 1¾′—3¼′ long and 1¼′—2′ wide; petioles stout, pubescent or puberulous, glandular at apex with large dark glands, or eglandular, ⅖′—⅗′ in length. Flowers appearing in March before the leaves, 1′ in diameter, on slender glabrous pedicels in 3 or 4-flowered sessile umbels; calyx-tube narrow-obconic, glabrous, the lobes oblong or oblong-ovate, about as long as the tube, rounded and laciniate at apex or entire, ciliate and glandular on the margins with small sessile glands, puberulous on the outer surface, hoary-tomentose on the inner surface, reflexed after anthesis; petals sometimes puberulous on the outer surface toward the base, ovate-orbicular to oblong-ovate, rounded at the narrow apex, crenulate, abruptly or gradually narrowed below into a short claw, about 3 times as long as the calyx-lobes; style longer than the stamens. Fruit ripening from the end of August to early October, subglobose to short-oblong, rounded at the ends, dark purple-red with a slight glaucous bloom, 1¼′—1⅓′ long and 1′—1¼′ in diameter, with thick succulent flesh; stone smooth obovoid to nearly circular, turgid, unsymmetric, narrowed and rounded at base, rounded or short-pointed at apex, ridged on the rounded dorsal edge with a broad thin ridge, thin, less rounded and grooved on the ventral edge, ¾′—1′ long and about ½′ wide.
A tree from 20°—25° high, with a trunk sometimes 8′—10′ in diameter, stout branches forming an open irregular head, and slender glabrous branchlets light orange-brown, very lustrous and marked by dark lenticels during their first winter and dull gray-brown the following year. Winter-buds ovoid, acute, glabrous, ¼′ long. Bark dark, nearly black or light gray, exfoliating in plate-like scales on young stems and large branches, becoming rough and deeply furrowed on old trunks.
Distribution. Open woods on rich alluvial bottom-lands, upland prairies and hillsides; southeastern Kansas (near Parsons, Labette County), through Arkansas to western Oklahoma (Navina, Logan County, Minca, Grady County), western Louisiana, northern and eastern Texas to the valley of the San Antonio River, ranging westward in Texas over the Edwards Plateau and to Brown and Palo Pinto Counties; in West Feliciana Parish, eastern Louisiana; in Coahuila and Nuevo Leon.
Passing into the following varieties:
Prunus mexicana var. reticulata Sarg. Differing in its thicker leaves more often narrowed at base, with more prominent reticulate veinlets, pubescent pedicels, globose fruit ripening late in September or in October, with thin, bitter, astringent flesh and dark deeply furrowed bark.
Distribution. Uplands and along the margins of river bottoms; neighborhood of Denison and Sherman, Grayson County, northern Texas.
Prunus mexicana var. polyandra Sarg.