Japan Flora: Winter annual; stems 10-30 cm. long, sometimes much-branched near base, reddish, sparsely reflexed-puberulent; leaves mostly basal, cordate or reniform, 1-2 cm. long and as wide, loosely ascending-pilose, sparsely round-toothed, the floral leaves suborbicu- lar or flabellate, 1-2.5 cm. wide, sessile; flowers 17-20 mm. long, sometimes cleistogamous, in dense sessile verticils, red; calyx about 5 mm. long with incurved or erect teeth; nutlets about 2 mm. long, trigonous, rounded at apex, narrowed below, rounded on back, usually white-spotted. May-June. Roadsides, cultivated fields, and waste grounds in lowlands.
Honshu, Shikoku, Kyushu; common. Ryukyus, Formosa, China, Korea to Europe, N. Africa, and widely adventive elsewhere