Description from Flora of China
Gaylussacia incurvata Griffith, Ic. Pl. Asiat. 4: t. 506. 1854; Pentapterygium rugosum (J. D. Hooker & Thomson ex Hooker) J. D. Hooker; Vaccinium rugosum J. D. Hooker & Thomson ex Hooker.
Shrubs. Twigs rounded, 2–3 mm in diam., hirsute towards apices, lenticellate. Leaves scattered, but towards end of insertion subsessile; leaf blade ovate-lanceolate or oblong, 5–10 × 2–3 cm, leathery, abaxially glabrous or pubescent, adaxially very rugose with impressed veins, pubescent, secondary veins 10–15 pairs, strongly raised abaxially, impressed adaxially, base obtuse or rounded, margin revolute, serrate, apex acuminate. Inflorescences corymbose, pendulous, 2- or 3-flowered; peduncle 3–10 mm. Pedicel deep red basally, ca. 3 mm, barely expanded. Calyx tube 1.8–3.8 mm, 5-angled, sparsely pubescent; limb divided ca. 2/3; lobes ovate-triangular, 5–6 mm. Corolla white, green, or deep red to purple, with purple or blood-red zig-zag bands, tubular, ca. 1.9 cm, strongly 5-angled, glabrous or pubescent on wings; lobes triangular. Filaments ca. 3 mm, puberulous; anthers ca. 1.6 cm, thecae papillate, tubules ca. 3 × as long as thecae, with minute spurs. Berry broadly hemispheric, ca. 8 mm or more, 5-ribbed; persistent calyx lobes to 1.2 cm. Fl. May–Jun.
Tsuga-Rhododendron forests, epiphytic on large trees; 1200–2400 m. SE Xizang (Dirangzong) [Bangladesh, Bhutan, NE India (Assam, Khasi hills), E Nepal, Sikkim].