Stems climbing with tendril-like petioles and leaf rachises, 3-6 m. Leaf blade pinnately 3- or 5-foliolate; leaflets ovate or broadly lanceolate to narrowly deltate, to 6.5 × 3.5 cm, margins entire; surfaces abaxially glabrous or very sparingly appressed-strigose on major veins. Inflorescences axillary, 3-12-flowered cymes or compound cymes or paniculate with cymose subunits. Flowers bisexual, often some unisexual (staminate) in same inflorescence; pedicel 1-3.5 cm, slender; sepals wide-spreading, not recurved, white, linear or elliptic to lanceolate or narrowly obovate, 0.9-2.2 cm, length ca. 2-3 times width, abaxially tomentose along margins, adaxially glabrous; stamens ca. 50; filaments glabrous; staminodes absent; pistils 5-10. Achenes broad, flat, conspicuously rimmed, minutely appressed-silky, sometimes sparsely so; beak 2-6 cm.
Flowering summer (Jul-Sep). Roadsides, thickets, and other secondary sites, edges of woods near creeks; 0-1000 m; introduced; Ont.; Ala., Ark., Conn., Fla., Ga., Ill., Ind., Kans., Ky., La., Md., Mass., Miss., Mo., Nebr., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn., Tex., Va., W.Va.; native to Asia (China, Korea, Japan).
Clematis terniflora is commonly cultivated as an ornamental. It is widely naturalized in the eastern United States. The name C . paniculata J. F. Gmelin was incorrectly used for this species by Thunberg in 1794.
Some authors have recognized two or more varieties in this species, correlated with their distribution in Asia, but in the study by H.Hara (1975), all of the varietal names were reduced to synonymy.
Stem climbing, 2-3 m; herbage glabrous; lfls mostly 5, ±coriaceous, triangular-ovate to broadly ovate, obtuse to acuminate, entire or rarely with an entire lobe, rounded to cordate at the base, the terminal one long-stalked; fls numerous, white, 2-3 cm wide; sep densely pubescent along the margins and on the back; achenes glabrous or minutely appressed-hairy, 8 mm; mature style plumose, 2-3 cm; 2n=16, 48, 64. Native of Japan, commonly cult. and often escaped. July-Sept. (C. dioscoreifolia; C. maximowicziana; C. paniculata Thunb., not J. F. Gmel.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Diagnostic Traits: vine with 3- or 5-foliate leaves, their margins entire; sepals 4, white, herbacous, wide-spreading; achenes with long styles that are short-plumose.
Somewhat invasive where there is a history of use as an ornamental.