Megacarpaea delavayi f. angustisecta O. E. Schulz; M. delavayi var. grandiflora O. E. Schulz; M. delavayi f. microphylla O. E. Schulz; M. delavayi var. minor W. W. Smith; M. delavayi f. pallidiflora O. E. Schulz; M. delavayi var. pinnatifida Danguy.

Herbs perennial, 15-86 cm tall. Trichomes retrorse, flattened, not crisped. Root cylindric, to 2 cm in diam. Caudex short, simple or rarely branched. Stems erect, branched above. Petiole of basal and lower cauline leaves (1-)2-5(-8) cm, considerably flattened at base; leaf blade oblong-oblanceolate in outline, appearing pinnately compound, (0.5-)5-15(-22) cm, sparsely to densely pubescent; lateral lobes 7-13 on each side of rachis, broadly ovate, oblong, or linear, (0.5-)1-2.5(-4.6) × 0.1-1(-2) cm, base decurrent, margin entire, irregularly serrate, or laciniate, apex acute or obtuse. Cauline leaves sessile, strongly auriculate or amplexicaul at base; leaf blade similar to that of basal leaves but with fewer lobes. Fruiting pedicels slender, (0.6-)0.8-1.5(-2) cm, usually strongly recurved, pubescent. Sepals purplish, oblong, 3-4(-4.5) × (1-)1.5-2(-2.5) mm, sparsely pubescent or glabrous. Petals lavender or deep purple, narrowly oblanceolate, oblong, or broadly obovate, entire or shallowly to deeply 3(-5)-lobed, (5-)7-10(-12) × (1-)3-4(-6) mm, base cuneate, apex rounded or subacute. Stamens 6; filaments (2.5-)3-4 mm; anthers narrowly oblong or linear, 1-1.5 mm. Fruit halves broadly obovate, (0.8-)1-1.2(-1.5) cm × (6-)7-8(-10) mm; wings 1-2 mm wide; replum 2.5-4 mm; locule 7-12 × 5-8 mm. Seed dark brown, broadly ovate, 4.5-6 × 3-4 mm. Fl. May-Aug, fr. Jul-Sep.

All of the synonyms above represent formal recognition of only a small portion of the enormous variation in Megacarpaea delavayi. The species is most variable in leaf morphology, flower size, petal shape and apex, and fruit shape and size. However, the variation in all of these characters is continuous in nature and does not show any correlation with geography. Therefore, it is more practical not to recognize any infraspecific taxa. The species is recorded here for the first time from Xizang and Myanmar; the records are based on Forrest 4342 (E) and Forrest 26890 (E, NY, US), respectively. This species is used for medicine and as a vegetable.

Swampy meadows, grassy slopes, open thickets; 3300-4800 m. Gansu, Qinghai, Sichuan, Xizang, Yunnan [Myanmar].