Polygonum filiforme Thunb., Fl. Jap. 163. 1784; P. virginianum auct. non L.: Hook. f., Fl. Brit. Ind. 5: 31. 1885; Tovara virginiana auct. non (L.) Rafin.: R.R.Stewart, Ann. Cat. Vasc. Pl. Pak. Kashm. 216. 1972; T. filiformis (Thunb.) Nakai in Rigakkai, 29 (4): 8. f. 60. 1926.

Erect, up to 1 meter tall, simple or branched, perennial herb. Stem branched, branches hollow. Leaves 8-18 x 4-8 cm, ovate and elliptic, entire, acute-acuminate, petiolate, petiole 1-3 cm long. Ochrea 0.75-2.0 cm long, ovate, tubular, ciliate, hispid. Inflorescence 12-40 cm long, lax, few flowered, slender, pedunculate raceme; peduncle 4-6 cm long, hispid. Flowers 2-3 mm across, distant, pedicellate, pedicel 0.5-1.0 mm. Ocreolae 1.0-3.0 mm long, distant, ciliate, hispid. Tepals 4, 2.0-3.5 x 1-1.5 mm, lanceolate, entire, acute. Stamens 5, filaments filiform, exserted. Ovary 0.5-1.0 x 0.25-0.5 mm biconvex, with two long filiform free hooked persistent styles. Nuts 1.5-2.0 x 0.75-1.25 mm biconvex, dark brown, shining, glabrous.

Type: Cirscit Juxta Nagasaki.

A Sino-Japanese element, grows between 1000-2500 m; Distribution: Pakistan, India (Sikkim-Bhutan) extending up to Japan.

Generally Antenoron filiforme (Thunb.) Roberty & Vautier and A. virginiana (L.) Roberty & Vautier are considered conspecific. However, the former species occurs only in Asia while the latter taxon is found in North America. Besides the geographical distribution the colour of fruiting perianth of both the species is also different.