Japan Flora: Glabrous, or thinly glandular-pilose on pedicels; stems erect, often branched at base, terete, 3-10 cm. long, sometimes decumbent at base; leaves spreading, linear-lanceolate or broadly linear, 7-10 nun. long, about 2 mm. wide, long-acuminate, entire; pedicels 1-1.5 cm. long or absent in cleistogamic flowers; calyx 4-6 mm. long, 5-parted nearly to the base, the segments linear-lanceohte; co­rolla purple, bilabiate, about 1J4 times as long as the calyx, the limb nearly as long as the tube; cleistogamic flowers often fasciculate in axils; capsules oblong, about 3 nun. long; seeds narrowly ovoid-oblong, about 0.5 mm. long, reticulate. Aug.-Oct. Wet places.

Honshu, Shikoku, Kyushu. Korea, Northeastern China, and Ryukyus.