Description from Flora of China
Clausia ussuriensis N. Busch.
Herbs annual, (10-)15-50(-65) cm tall, sparsely to densely hispid with subsetose trichomes to 3.5 mm, these mixed with much shorter ones, glandular on all parts except petals and stamens, gland stalks to 0.4 mm. Stems erect, often simple. Middle cauline leaves with petioles 2-5 mm; leaf blade elliptic or elliptic-lanceolate, 15-3.5 cm × 5-10 mm, base cuneate, margin serrate-dentate, apex acute. Fruiting pedicels divaricate, straight, slender, 7-15 mm, glandular. Sepals narrowly oblong, (3.5-)5-6 × 1.5-2 mm, glandular and often also setose. Petals lavender or purplish, broadly obovate, (10-)12-18 × (4-)6-8 mm, apex subemarginate; claw 5-7 mm. Filaments of median stamens 5-7 mm, united; filaments of lateral stamens 3-5 mm; anthers narrowly oblong, 1.5-2 mm, apex obtuse. Ovules 30-60 per ovary. Fruit (2-)3-6(-8) cm × 1.5-2 mm, glandular, straight, divaricate or ascending, subtorulose, flattened, midvein prominent; style (1-)2-3 mm; stigma slightly lobed. Seeds brown, oblong-ovate, 2-2.5 × 1.2-1.4 mm, with a narrow wing to 0.5 mm wide; cotyledons accumbent. Fl. and fr. Jun-Sep. 2n = 14.
Although the present authors have seen no material from China, this species was described from Manchuria and was recorded from China in Pl. Vasc. Orient. Extr. Sov. 3: 111. 1988. It is likely that the species occurs in SE Heilongjiang and/or NE Jilin.
Flood plains, sandy river banks; 200-400 m. ?Heilongjiang [Russia (Far East)].