19. Rhamnus subapetala Merrill, J. Arnold Arbor. 23: 179. 1942.
紫背鼠李 zi bei shu li
Shrubs scandent, rarely small trees, dioecious, 3-9 m tall, unarmed. Branchlets brown, with numerous tuberculate lenticels. Leaves alternate; stipules lanceolate, 1-1.5 mm, caducous; petiole 5-18(-25) mm, glabrous; leaf blade adaxially yellow-purple or pale purple when dry, stiffly papery or subleathery; small leaf blades 2-6 cm; large leaf blades oblong-elliptic or oblong, 7.5-15 × 2-6.5 cm, abaxially glabrous or clustered hairy in vein axils, adaxially glabrous, lateral veins 5-8 pairs, midvein prominent abaxially, impressed adaxially, with ± conspicuous reticulate veins, base cuneate or rounded, margin slightly revolute when dry, shallowly or inconspicuously serrate, apex caudate-acuminate or acuminate, rarely rounded, erect or curved mucronate, mucro 1-2 mm. Flowers green, unisexual, 5-merous, solitary or 2- or 3-fascicled in axillary, lax cymose racemes or cymose panicles; bracts leaflike, to 6 cm. Pedicels ca. 1 mm, puberulent. Sepals triangular, ca. 1.5 mm, apex acute or slightly acuminate. Petals absent. Female flowers with minute, rudimentary stamens; ovary 3-loculed; style short, deeply 3-cleft, caducous. Drupe (immature) globose-obovoid, ca. 5 mm, with 2 or 3 stones. Seeds abaxially with a margined furrow extending over ca. 2/3 of length. Fl. Jun-Jul, fr. Aug-Nov.
Sparse or dense forests in valleys; 700-2000 m. W Guangxi, S Yunnan [Vietnam].
This species is similar to Rhamnus coriophylla, but the latter differs in having leathery leaves that do not turn purple when dry, apex acuminate, and short petioles.