Stems erect, 1.5-4(-7) dm, moderately to densely villous, sometimes sparsely so near nodes. Leaves simple. Leaf blade ovate-elliptic to broadly ovate, unlobed, 5-14 × 3.5-11 cm, leathery, prominently reticulate adaxially; surfaces abaxially glabrous or sparsely villous-tomentose on veins, not glaucous. Inflorescences terminal, flowers solitary; bracts absent. Flowers narrowly urn-shaped; sepals pale blue-violet to purple, pale green toward tips, lanceolate, 2-4 cm, margins not expanded or 1-3 mm wide, thin or ± thick, not crispate or slightly crispate, tomentose, tips acuminate, spreading to recurved, abaxially glabrous to sparsely villous. Achenes: bodies proximally pubescent with silky or sparse short hairs, distally cobwebby-tomentose; beak 1.5-3(-3.5) cm, proximally silky-tomentose, sparsely appressed-pubescent to nearly glabrous toward tip. 2 n = 16. Flowering spring. Calcareous prairies and glades; 100-700 m; Kans., Mo., Nebr. R. O. Erickson (1943) separated the Missouri plants as Clematis fremontii var. riehlii R. O. Erickson on the basis of their supposedly greater height and more widely spaced, proportionately narrower leaves. As noted by C. S. Keener (1967), however, so much overlap occurs in the ranges of variation of the Missouri and the Kansas-Nebraska populations that recognition of these varieties is not possible.
Stems erect, 2-6 dm, simple or branched, villous or glabrate; lvs subsessile, lance-elliptic to broadly ovate, firm, reticulate, glabrescent in age, the larger ones mostly 7-13 נ4-9 cm; mature peduncles mostly 3-6 cm, shorter than the uppermost lvs; cal urceolate; sep lanceolate, long-acuminate, densely tomentose on the margins, otherwise glabrous or nearly so; achenes densely tomentose; mature style mostly 1.5-3 cm, tomentose (not plumose) below, glabrous above the middle; 2n=16. Barrens and prairies; e. and s. Mo.; disjunct in c. Kans. and adj. Neb. Apr., May.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.