Description from Flora of China
Viola biflora Linnaeus var. platyphylla Franchet.
Herbs perennial. Rhizome erect, ca. 3.5 cm, ca. 5 mm in diam., densely noded, with numerous fibrous roots. Stems 1-3, erect, to 11 cm tall, 2.5-3 mm in diam., glabrous, conspicuously striate, leafless in middle and lower parts. Basal leaves few or withered; stipules conspicuous, membranous, margin remotely dentate; petiole 5-7 cm, slender, very narrowly winged; leaf blade reniform, abaxially glabrous except along veins, adaxially sparsely puberulous. Upper leaves clustered at apex of stem; stipules ovate, 4-5 mm, herbaceous, margin remotely dentate or subentire; petiole ca. 1.5 cm; leaf blade reniform, ca. 1.5 × 2.5-4 cm, ± fleshy, both surfaces sparsely puberulous, margin obtusely serrate, apex usually obtuse, rarely mucronate. Flowers few, yellow, long pedicellate; pedicels linear, 2-3.5 cm, not bracteolate. Sepals linear, ca. 5 mm, 3-veined, margin subentire, basal auricles short. Petals obovate-oblong, glabrous, upper ones ca. 7.5 × 2.5 mm, lateral ones and anterior one ca. 8 × 4 mm; spur saccate, ca. 1.5 mm; spur of anterior stamens short. Ovary ovoid-globose, ca. 2 mm, glabrous; styles ca. 1 mm, base conspicuously geniculate, 2-lobed in upper part, lobes narrow and thick. Fl. Jul, fr. Sep.
● Moist places in mountain ravines; 2800-3200 m. NW Yunnan.