Flowering from June to September; fruiting from September to October.
Clematis tangutica var. tangutica is close relative of Clematis tangutica var. obtusiuscula, but differs from the latter in its sepal apices ± cuspidate (vs. acute).
Clematis tangutica is occurring in Gansu, Qinghai, S Shaanxi, W Sichuan, Xinjiang, Xizang of China, Kazakhstan.
Vines woody, sometimes dwarf, erect shrublets when growing in dry, sandy, or gravelly regions. Branches shallowly 6-8-grooved, puberulous, glabrescent. Leaves 1-2-pinnate; petiole 2-6 cm long; leaflet blades rhombic-ovate to narrowly ovate, 1-6 cm long, 0.7-2.8 cm wide, papery, often 3-lobed near base or undivided, both surfaces sparsely puberulous on veins, base broadly cuneate, rounded, or subcordate, margin denticulate, apex acute to ± obtuse; basal veins abaxially flat. Flowers solitary, terminal, or sometimes also in axillary 1-3-flowered cymes, 2-6 cm in diameter; peduncle 0.3-3 cm long; bracts short petiolate, similar to leaflets. Pedicel 3.5-16 cm long, sericeous-puberulous to subglabrous. Sepals 4, yellow, sometimes tinged purple, ascending, narrowly ovate, lanceolate, or oblong, 1.5-4 cm long, 0.6-1.5 cm wide, abaxially sparsely puberulous, adaxially glabrous or rarely puberulous, margin abaxially velutinous, apex cuspidate. Stamens 5-11 mm long; filaments puberulous; anthers narrowly oblong, 2-3 mm long, glabrous, apex obscurely apiculate to subobtuse. Ovaries puberulous. Style 0.9-1.5 cm long, densely villous. Achenes rhombic-obovate, ca. 4.5 long, 2.2 mm wide, puberulous; persistent style to 5 cm long, plumose.
The chromosomal number of Clematis tangutica is 2n = 16 (Bhattacharjee and Sharma, 1980; Serov, 1989).
Growing in scrub, grassy areas, gravelly river banks; 1300-4900 m.
