Japan Flora: Glabrous annual; stems rather fleshy, erect, 10-25 cm. long, usually branched at base; leaves spreading, lanceolate, subobtuse, entire, weakly few-nerved from the base, sessile; flowers solitary in axils, sessile, the bracteoles simulating the calyx-lobes; calyx 3-4 mm. long, 5-partcd nearly to the base, the segments lanceolate, subobtuse; corolla white, about 6 mm. long, the limb rather short, bilabiate; capsules globose, 3-5 mm. across, slightly longer than the calyx; seeds lanceolate, about 0.7 mm. long. May-July. Wet places especially in paddy fields.

Honshu, Kyushu. Korea, Amur, and Ussuri.