Smilax myrtillus var. dulongensis H. Li; S. rigida Wallich ex Kunth subsp. myrtillus (A. de Candolle) T. Koyama; S. rigida var. myrtillus (A. de Candolle) T. Koyama.

Shrubs erect. Stem densely branched, 50--100 cm, sparsely prickly; branchlets usually 4-angled, with winglike edges. Petiole 1--4 mm, basally auriculate; auricles paired, lanceolate to ovate, 1--2 × ca. 0.5 mm, membranous, margin lacerate-fimbriate; abscission zone at middle; tendrils absent. Leaf blade usually rhombic-ovate, 1--5 × 0.6--2.5(--3) cm, thinly papery, main veins 3(--5), raised adaxially. Inflorescence of 1 umbel, basally not prophyllate; peduncle 5--10 mm; umbels of both sexes 2--10-flowered. Male flowers: tepals purplish green, ca. 1.5 × 0.4--0.6 mm; stamens ca. 0.5 mm. Female flowers: tepals ca. 1 × 0.3 mm; staminodes 3. Berries blue-black, globose, 6--8 mm in diam. Fl. Jul, fr. Oct--Nov.

Forest, forest margins, thickets; 1600--3100 m. SE Xizang, Yunnan [Bhutan, India, Myanmar].