Clematis addisonii
Clematis addisonii, commonly known as Addison's leatherflower or Addison's virgin's-bower, is a rare species of flowering plant in the family Ranunculaceae. It is endemic to western Virginia in the United States, where it occurs in calcareous woodlands and barrens.
Description
Clematis addisonii is an herbaceous perennial with ascending to erect stems typically 0.6–1 m in length, occasionally somewhat viney.
Leaves are mostly simple, though distal leaves on vigorous plants may be 1-pinnate. Leaflets (when present) are ovate, unlobed, and not prominently reticulate. The lower leaf surface is characteristically glaucous and glabrous.
Flowers are solitary, borne terminally or axillary, and are ovoid to broadly urn-shaped. Sepals are purple to reddish-purple, often paling toward the tips, and measure 1.2–2.5 cm long.
Fruits are achenes with plumose styles 2.5–3.5 cm long.
Taxonomy
The species was first described by Nathaniel Lord Britton in 1890.
It has historically been placed in the genus Viorna as Viorna addisonii (Britton) Small, reflecting its placement within Clematis subgenus Viorna.
Distribution and habitat
Clematis addisonii is restricted to Botetourt, Montgomery, Roanoke, and Rockbridge counties in western Virginia.
It occurs in dry to mesic calcareous woodlands, barrens, and rock outcrops, typically over dolostone of the Elbrook Formation.
The species is typically found at elevations of approximately 200–600 m.
Ecology
The species flowers in spring to early summer.
It is associated with open or lightly shaded habitats and may decline with canopy closure.
Conservation
Clematis addisonii is ranked as G1–G2 (critically imperiled to imperiled) by NatureServe, with a rounded status of G1.
The species is known from a small number of populations, with approximately 6–20 occurrences and about 11 documented in recent decades.
Major threats include habitat loss, development, invasive species, deer browsing, and habitat fragmentation.
The species is endemic to a narrow range and has experienced population declines over time.
It has been reviewed multiple times for potential listing under the U.S. Endangered Species Act but is not currently federally listed.
Conservation efforts
The species is included in the National Collection of the Center for Plant Conservation, with living collections maintained by partner institutions.
Conservation efforts focus on habitat management, ex situ cultivation, and maintaining genetic diversity.
Horticulture
Although rare in the wild, Clematis addisonii can be cultivated in well-drained, calcareous soils and partial shade. It is valued for its nodding, urn-shaped flowers and compact, non-climbing habit.
References
addisonii Category:Endemic flora of Virginia Category:Plants described in 1890 Category:Taxa named by Nathaniel Lord Britton