Description from Flora of China
Viola brachysepala Maximowicz; V. mirabilis var. brachysepala (Maximowicz) Regel; V. mirabilis var. brevicalcarata Nakai; V. mirabilis var. glaberrima W. Becker; V. mirabilis f. latisepala W. Becker; V. mirabilis var. platysepala Kitagawa; V. mirabilis var. subglabra Ledebour.
Herbs perennial, acaulescent before anthesis, later gradually caulescent, 6-23 cm tall. Rhizome erect or oblique, to 4 cm, 3-7 mm in diam., conspicuously noded, much branched in upper part, with dense brown or red-brown remains of scalelike stipules; roots numerous, brown, harder when dry. Stem erect, puberulous or glabrous, with only 1 leaf at middle, densely leaved in upper part. Stipules large; basal ones red-brown, scalelike, ovate, ca. 1 × 0.5 cm, apex obtuse or acuminate; upper ones brownish, broadly lanceolate, 0.8-1.7 × 0.3-0.5 cm, glabrous, margin entire; those of cauline leaves lanceolate, margin usually ciliate; petioles of basal leaves longer, 5-15 cm, puberulous or glabrous, narrowly winged; those of cauline leaves unequal in length, middle ones ca. 8 cm, upper ones very short or nearly absent; leaf blade broadly cordate or reniform, 3-5 × 4-6 cm, abaxially puberulous along veins, adaxially puberulous, base broadly cordate, margin shallowly crenate, often involute at anthesis, apex rounded or mucronate. Flowers purplish or violet, large; those in basal leaf axils usually not fruiting, pedicels to 10 cm, with 2 linear bracteoles in upper part; those in cauline leaf axils fruiting, pedicels short, with bracteoles at or below middle. Sepals oblong-lanceolate, ovate-lanceolate, or lanceolate, 7-16 × 2-4 mm, apex acute, basal auricles ca. 2 mm, 3-veined, margin ciliate or subglabrous, apex obtuse, outer 3 usually conspicuously longer and broader than inner 2. Petals obovate, lateral ones distinctly bearded, anterior one to 2 cm (spur included), spur robust, ca. 5 mm, usually curved upward, rarely straight, apex obtuse. Ovary glabrous; styles suberect at base or slightly curved forward, slightly thickened in upper part, slightly curved and shortly beaked at apex, not papillose; stigma hole narrow. Capsule ellipsoid, 1-1.4 cm, glabrous. Fl. May, fr. May-Aug. 2n = 20.
Broad-leaved forests, needle-leaved and broad-leaved mixed forests, forest margins, thickets, grassy slopes; below 2000 m. Gansu, N Hebei, Heilongjiang, Jilin, Liaoning, Nei Mongol, Ningxia, Shanxi [Japan, Korea, Mongolia, Russia].