Description from Flora of China
Hypecoum chinense Franchet.
Herbs, summer annual, ± glaucous. Cotyledons lanceolate. Leaves numerous; petiole 1.5-8 cm, shortly and broadly vaginate at base; blade narrowly oblanceolate, 5-20 × 1-3 cm, pinnate; primary leaflets 4-9 pairs, broadly ovate, 0.4-2 cm, almost sessile, pinnatifid; lobules lanceolate, ovate, or narrowly elliptic to obovate, 2-4 mm, apex acute. Flowering stems few to many, 5-40 cm, dichotomously branched; bracts paired, 0.5-3 cm, lower ones biternate to sub-bipinnate, gradually smaller and less divided upward, uppermost linear. Sepals green, ovate or ovate-lanceolate, 2-3(-4) × 1-1.5(-2) mm, margin membranous, entire, rarely toothed. Petals white or pale lavender, apically green (in type description Hypecoum chinense said to have yellowish flowers); outer petals obovate, 6-9 × 4-6 mm, entire; inner petals 3-parted to less than 1/2; lateral lobes broadly oblong, apex obtuse; middle lobe spatulate-orbicular, ca. 2 mm, shortly stalked or sessile, margin incurved, almost entire or slightly denticulate. Stamens with obscure nectaries; anthers 1-1.5 mm. Ovary with up to ?20 ovules. Capsule erect, linear, 3-4 cm × 1-1.5 mm, breaking up into 15-18 segments when mature, each segment with 1 seed. Seeds flattened, D-shaped. Fl. and fr. Jun-Sep. 2n = 42.
The specimen Harry Smith 4371 (Sichuan: Barkam Xian, Matang, 31°53′N, 102°43′E, 3400 m, 17 Sep 1922, UPS) deviates considerably in its less divided leaves with very broad serrate leaflets and possibly represents an undescribed taxon.
Hypecoum alpinum C. H. An (Fl. Xinjiang. 2(2): 373. 1995: type not recoverable, possibly lost) has, according to the description, leaves and flowers like H. leptocarpum but differs in being very dwarf, perennial, fleshy, and in having a very short capsule and smooth seeds.
Slopes, grasslands, valleys, river sands, gravel slopes, sandstone; (1700-)2700-5000 m. Gansu, NW Hebei, Nei Mongol, Qinghai, Shaanxi, Shanxi, W Sichuan, Xinjiang, Xizang, NW Yunnan [Afghanistan, Bhutan, India, Mongolia, Nepal, Tajikistan].