Clematis viorna L.

A half-woody climber 6 to 10 ft high. Leaves mostly pinnate; leaflets, usually five, of various sizes and shapes, the basal ones largest, mostly two- or three-lobed, or trifoliolate, often heart-shaped at the base, 11⁄2 to 2 in. long and wide; the upper ones not lobed, ovate, 3⁄4 to 11⁄2 in. long; all of them without teeth and often glabrous. Flowers nodding, solitary on stiff stalks 2 or 3 in. long; sepals very thick and leathery, pointed, 1 to 11⁄4 in. long, dull reddish purple, greenish white or yellowish inside. The sepals touch and form a bell-shaped flower, slightly narrowed towards the mouth where the points are curved back. Seed-vessels with brownish feathery styles 1 in. long.

Native of the eastern United States, introduced in 1730. It is the type species of a group of Clematis whose converging sepals give an urn- or bell-shape to the flower. The stems die back in winter to the woody base of the plant. Although interesting and curious, this species is not particularly attractive.