7. Clematis viorna L. (leather flower, vase vine)

Pl. 513 i, j; Map 2355

Plants with perfect flowers, the stems woody (at least toward the base), twining, 1–4 m long. Well-developed leaves pinnately 5–9-foliate or twice pinnately compound, usually herbaceous in texture, the minor veins not raised, the leaflets undivided or 2- or 3-lobed, the margins entire, the upper surface green, the undersurface green or pale, hairy (sometimes very sparsely so), at least along the main veins. Flowers solitary or in groups of 2 or 3. Perianth more or less cylindrical, the sepals 17–25 mm long, erect or with only the apical 3–5 mm reflexed, purple, thickened and leathery, with thin, crisped margins absent or less than 1 mm wide, the inner surface glabrous, the outer surface hairy, the margins densely hairy. Fruits with the beak 2–6 cm long, plumose with long, spreading hairs. 2n=16. May–June.

Scattered sites in the Ozark and Ozark Border Divisions (eastern United States, west to Missouri). Open or wooded ridgetops, bluffs, rocky slopes, around rock outcrops and edges of glades, on limestone, dolomite, and sandstone.