Japan Flora: Glabrous, erect perennial, 40-60 cm. high, usually unbranched; stems angled; leaves narrowly oblanceolate to broadly linear, 2-4.5 cm. long, 3-5 mm. wide, obtuse, entire, black-dotted, sessile or subsessile; in­florescence racemose, terminal, many-flowered, erect, the bracts linear, the pedicels 12-20 mm. long, 2 or 3 times as long as the bracts; calyx-segments lanceolate, acuminate, entire; corolla white, about 5 mm. across, the lobes obovate, obtuse; capsules small.  Apr. Wet places, near ponds and rivers in low­lands.

Honshu, Kyushu; rare. Korea.