24. Clematis crispa Linnaeus, Sp. Pl.  1: 543.  1753.  
Marsh clematis, curly clematis, blue-jasmine  
Viorna crispa (Linnaeus) Small; V.obliqua Small
Stems  viny, to 3 m, glabrous or sparsely to moderately pilose-pubescent, denser at nodes.  Leaf blade  1-2-pinnate or rarely a few simple or 3-foliolate; leaflets 4-10 plus additional ± tendril-like terminal leaflet, usually lanceolate to ovate, occasionally linear, unlobed or proximally 3-5-lobed, (1.5-)3-10 × (0.1-)0.4-4(-5) cm, thin, not conspicuously reticulate; surfaces glabrous, not glaucous.  Inflorescences  terminal, 1-flowered; bracts absent.  Flowers  bell-shaped; sepals distally strongly spreading to recurved, violet-blue, lanceolate, 2.5-5 cm, margins proximally thick and tomentose, distally broadly expanded, 2-6 mm wide, thin, crispate, less conspicuously tomentose than proximal portion, or glabrate, tips acuminate, abaxially glabrous.  Achenes:  bodies appressed-puberulent; beak 2-3.5 cm, appressed-puberulent. 2 n  = 16.
Flowering spring-summer. Low woods, bottomlands, swamps; 0-200 m; Ala., Ark., Fla., Ga., Ill., Ky., La., Miss., Mo., N.C., Okla., S.C., Tenn., Tex., Va.
Clematis crispa is highly variable in leaflet width, and conspicuous variation may occur on a single plant (R.O. Erickson 1943); no discontinuity or geographic correlation exists that would permit the recognition of varieties. The dilated, petaloid sepal tips and thin, crispate, broadly expanded sepal margins are diagnostic for this species.