Viola triangulifolia W. Becker

Herbs perennial, caulescent, 13-35 cm tall. Rhizome usually obliquely ascending, deep brown, short, stout, densely noded, with numerous stout rootlets. Stems solitary or several fasciculate, erect, slender, glabrous. Basal leaves 2-5, usually withered early; petioles 3-6.5 cm; blades broadly ovate or ovate, 1-2 × 1.5-2.8 cm, base cordate, apex acute. Cauline leaves long petiolate; stipules free, lanceolate or linear-lanceolate, 0.5-1 cm, herbaceous, margin entire or remotely denticulate, often ciliate; blades ovate-triangular to narrowly triangular, 2-5 × 2-3.5 cm at base, both surfaces glabrous, base cordate or truncate, margin shallowly serrate, apex acute. Flowers solitary in axils of cauline leaves, white, purple striate, small; pedicels usually subequaling leaves, sometimes exceeding leaves, slender, 2-bracteolate at upper part; bracteoles opposite, linear. Sepals ovate-lanceolate or lanceolate, ca. 3 × 0.8-1.2 mm, apex acuminate, basal auricles ca. 0.5 mm, margin narrowly membranous. Upper petals narrowly obovate, 5-7.5 × ca. 2.5 mm, lateral ones oblong, 5-8 × ca. 2 mm, bearded, anterior one shorter, spatulate, ca. 6 mm (spur included); spur shallowly saccate, 1-1.5 mm, ca. 2 mm in diam. Anthers ca. 2 mm, appendage of connectives ca. 1.5 mm, spur of 2 anterior stamens shorter, square, subtriangular, ca. 1.1 × 0.8 mm. Ovary ovoid-globose, ca. 1.5 mm, glabrous; styles clavate, ca. 1.3 mm, base slightly geniculate forward, conspicuously thickened upward; stigmas conspicuously thickened on lateral and abaxial sides, margin obliquely spreading, flat in central part, shortly beaked in front, with a larger stigma hole at tip of beak. Capsule ellipsoid, small, 5-6 mm, glabrous. Fl. Apr-May, fr. May-Sep.

Anhui, Fujian, Guangdong, Guangxi, Guizhou, Hubei, Hunan, Jiangxi, Zhejiang.

● Streamsides in mountain valleys, forest margins, roadsides; 200-1800 m.

Viola triangulifolia là một loài thực vật có hoa trong họ Hoa tím. Loài này được W. Becker miêu tả khoa học đầu tiên năm 1929.

三角叶堇菜（学名：Viola triangulifolia）是堇菜科堇菜属的植物，是中国的特有植物。分布于中国大陆的广西、广东、江西、浙江、湖南、福建等地，生长于海拔200米至1,200米的地区，一般生于山谷溪旁、林缘以及路旁，目前尚未由人工引种栽培。