Japan Flora: Slender glabrous diffuse annual; stems branched, 10-20 cm. long, nearly terete; leaves in verticils of 4-7, oblanceolate to broadly linear, 12-25 nun. long, 2-7 mm. wide, obtuse or subacute, 1-nerved, gradually narrowed to a short petiole; flowers several, in axillary fascicles, the pedicels 2-5 mm. long, the sepals oblong, obtuse or rounded, 1.5-2 mm. long, 3-nerved; capsules ovoid-ellipsoid, about 3 mm. long; seeds yellow-brown, lustrous, reniform-orbicular, about 0.3 mm. across, with few raised concentric lines；July-Aug.

Naturalized in our area,