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.
Herbs perennial. Rhizomes stout. Stems erect, 50-80 cm tall, striate, appressed hispid, swollen at nodes. Petiole 1-1.5 cm, appressed hispid; leaf blade elliptic or narrowly elliptic to ovate, rarely obovate, 6-15 × 4-8 cm, both surfaces appressed hispid, base cuneate, margin entire, apex acute or acuminate; ocrea tubular, 5-10 mm, membranous, shortly ciliate. Inflorescence terminal or axillary, 15-35 cm, slender, laxly flowered; bracts funnel-shaped, 2-3 mm, ciliate, 1-3-flowered. Pedicel 3-4 mm. Perianth rose, 4-parted; tepals ovate, ca. 3 mm, accrescent. Stamens usually 5, included. Styles 2, persistent, enlarged and indurate at maturity, 3.5-4 mm, deflexed and hooked at apex, long exserted from perianth. Achenes included in persistent perianth, dark brown, shiny, ovoid, biconvex, smooth. Fl. Aug-Oct, fr. Sep-Nov.
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.