Description from Flora of China
Combretum auriculatum C. Y. Wu & T. Z. Hsu (1977), not Engler & Diels (1899); C. incertum Handel-Mazzetti; C. linyenense Handel-Mazzetti; C. purpurascens Handel-Mazzetti; C. wallichii var. pubinerve C. Y. Wu; Terminalia mairei H. Léveillé.
Lianas to 6 m tall. Bark longitudinally fibrous peeling, sparsely black lenticellate. Branchlets together with petioles puberulous and densely brown scaly, glabrescent. Leaves opposite or subopposite; petiole 4-10 mm; leaf blade variable in shape, oblong-elliptic, elliptic, broadly elliptic, ovate, obovate, or suborbicular, 4-15 × 2-7 cm, both surfaces glabrous at maturity except abaxially often with tufts of brown to white hairs in axils of lateral veins, or rarely abaxially persistently sparsely ferruginous pilose and densely so on veins, both surfaces usually not scaly but often densely green or white verruculose, base attenuate or obtuse-rounded, apex acuminate, or rounded or obtuse-rounded and mucronate; lateral veins in 5-9 pairs. Inflorescences terminal and axillary, simple, narrowly cylindric spikes 3-9 cm, sometimes grouped at branchlet apex and forming a panicle; axes puberulous, brown scaly; bracts caducous, linear or linear-lanceolate, 2.5-4 mm. Flowers strongly scented. Calyx tube in middle part broadly funnelform, distally broadly campanulate to salverform, 3.5-5 mm, abaxially glabrous and brown scaly, adaxially with a ring of exserted, dense, coarse hairs; lobes 4, erect, deltoid or broadly triangular, 1-1.5 mm, apex acuminate or shortly so. Petals 4, yellow to green, ca. 1.5 mm, clawed; limb oblanceolate. Stamens 8, exserted, ca. 5 mm. Fruit purple or red, glossy, ± globose, 4-winged, 1.7-3.3 × 1.8-3 cm, glabrous, white or golden scaly. Fl. Mar-Aug, fr. Jul-Nov.
The record from N Vietnam (Cao Bang, in 1999) is apparently new and is based on P. K. Loc et al. CBL 1351 (MO).
Combretum wallichii var. pubinerve C. Y. Wu (Fl. Yunnan. 1: 90. 1977), described from W Yunnan (Lushui), differs from typical C. wallichii in having a suborbicular leaf blade, abaxially sparsely ferruginous pilose at maturity, densely so on veins. Because the species is so variable in leaf blade shape, only the hairiness would reliably separate var. pubinerve, and that character does not seem sufficient to justify formal recognition of a variety.
Combretum auriculatum C. Y. Wu & T. Z. Hsu (in C. Y. Wu, Fl. Yunnan. 1: 90. 1977), described from SW Yunnan (Cangyuan), appears to be a form of C. wallichii with a ± oblanceolate leaf blade slightly auriculate-cordate at the base. The name is illegitimate because it is a later homonym of C. auriculatum Engler & Diels (in Engler, Monogr. Afric. Pflanzen-Fam. 3: 79. 1899), described from tropical Africa.
Gangopadhyay & Chakrabarty (J. Econ. Taxon. Bot. 17: 679-682. 1993) recognized six varieties within Combretum wallichii: the typical variety, three varieties from outside China, and two varieties based on C. griffithii and C. yunnanense. The last two taxa are indeed similar to C. wallichii but, in the present treatment, we prefer to maintain C. griffithii separately, including C. yunnanense within it as C. griffithii var. yunnanense.
Mixed forests, woods, thickets, scrub, mountain slopes and valleys, shaded limestone ravines, streamsides, roadsides; (500-)800-2200(-3200) m. Guangxi, Guizhou, Sichuan, Yunnan [Bangladesh, Bhutan, India, Myanmar, Nepal, N Vietnam].