Raleigh Ecological Services Field Office
Conserving the Nature of America

Cooley’s Meadowrue (Thalictrum cooleyi)

Cooley’s Meadowrue

Cooley’s Meadowrue

Family: Buttercup (Ranunculaceae)

Federal Status: Endangered, listed February 7, 1989

Best Search Time: mid June through early July

Description: Cooley's meadowrue (Thalictrum cooleyi Ahles) is a perennial herb which grows from a rhizome. The stems are usually 3.3 feet (ft) (1 meter; m) in height, but sometimes grow as high as 6.6 ft (2 m) on recently burned sites. Under ideal conditions, in full sun, these stems are erect; however, when shaded they are lax and may trail along the ground or lean on other plants. The compound green leaves are divided into three parts and the leaflets are lance-shaped and less than 2 centimeters long. The plant has both basal and stem leaves. All parts of the plant are glabrous, having virtually no hairs or glands. Each plant is unisexual, and the male to female ratio is 3 to 1. The flowers have no petals. The sepals on the male plants are pale yellow to white. There are numerous stamens, and the filaments are pale lavender. Female plants have green sepals, and their short-stalked, ribbed carpels develop into narrowly ellipsoidal achenes. Cooley's meadowrue flowers in mid June to early July. The fruits are spindle-shaped carpels which develop into 6 millimeter long achenes, maturing in August or September, and remaining on the plant into October. If the plants grow in partial shade instead of full sun, flowering may be delayed by as much as two weeks.

Habitat: Cooley's meadowrue occurs on circumneutral soils in grass-sedge bogs and wet pine savannahs and savannah like areas. It may also grow along fire plow lines, in roadside ditches, woodland clearings, and powerline rights-of-way, and needs some type of disturbance such as fire or mowing to maintain its open habitat. Plants often found growing with Cooley’s meadowrue include tulip poplar growing with bald cypress and/or Atlantic white cedar.

Distribution: Currently, Cooley’s meadowrue is known from North Carolina, Georgia and Florida. The North Carolina populations are located in Brunswick, Columbus, Onslow and Pender counties including several sites protected by The Nature Conservancy and NC Division of Parks and Recreation. There is one population of Cooley’s meadowrue in Walton County, Florida. In addition, there are several populations of Cooley’s meadowrue in Worth and Doughtery counties, Georgia, though the taxonomy of these populations is unresolved at this time.

Threats: Cooley’s meadowrue is threatened by loss of habitat, ecological succession, clearing for agriculture, forestry, herbicide application to power line corridors, development and road maintenance and construction projects.


Buchanan, M.F. and J.T. Finnegan. 2010. Natural Heritage Program List of the Rare Plant Species of North Carolina. NC Natural Heritage Program, Raleigh, NC.

U.S. Fish and Wildlife Service. 1994. Cooley’s Meadowrue Recovery Plan. U.S. Fish and Wildlife Service, Atlanta, GA. 29 pp.


  • Ahles, H.E. 1959. Thalictrum cooleyi sp. nov. Brittonia 11:68-70, April 1959.
  • Coile, Nancy C. 2000. Notes on Florida's Regulated Plant Index (Rule 5B-40), Botany Contribution 38. Gainesville, Florida: Florida Dept. of Agriculture and Consumer Services, Division of Plant Industry.
  • FNAI. 2000. Field Guide to the Rare Plants and Animals of Florida online. Florida Natural Areas Inventory.
  • Hardin, D.; White, D. L. 1989. Rare Vascular Plant Taxa Associated with Wiregrass (Aristida stricta) in the Southeastern United States. Natural Areas Journal. 9, 4: 1989
  • Keener, C.S. 1976. Studies in the Ranunculaceae of the Southeastern United States II. Thalictrum L. Rhodora, Vol. 78, 815, 1976 pp 457-472.
  • Kral, R. 1983. A report on some reare, threatened, or endangered forest-related vascular plants of the south. Tech. publ. R8-TP-2. USDA Forest Service 4:28-431.
  • Leonard, S. 1987. Inventory of populations of Thalictrum cooleyi and its occurrence sites in North Carolina. Report to the North Carolina Natural Heritage Program. Raleigh, NC. 16pp.
  • Mansberg, L. 1985. Thalictrum cooleyi; draft global element ranking form prepared for the Nature Conservancy; North Carolina Natural Heritage Program, Raleigh, NC. 16pp.
  • The Nature Conservancy. 1986. Lanier quarry Savanna Preserve. The Nature Conservancy News. 36, 6: 28.
  • The Nature Conservancy. 1997. 1997 Species Report Card: Cooley's meadowrue. Arlington, VA: The Nature Conservancy, Natural Heritage Network (NatureServ). p.21.
  • North Carolina Botanical Garden. 1995. 1995 Annual report on taxa in the national collection for North Carolina Botanical Garden. Annual report to the Center for Plant Conservation. p.1.
  • Park, M.M. 1992. A biosystematic study of Thalictrum section Leucocoma (Ranunculaceae). Ph.D. dissertation, Pennsylvania State University.
  • Radford, A.E., H.E. Ahles and C.R. Bell. 1968. Manual of the Vascular Flora of the Carolinas. University of North Carolina Press, Chapel Hill, N.C.
  • Rayner, D. 1980. Status report on Thalictrum cooleyi Ahles, submitted to U.S. Fish and Wildlife Service, Atlanta, GA.
  • Rees, M.D. 1989. Final Listing Rules Approved. Endangered Species Technical Bulletin. 14, 3: 7.
  • Rome, A. 1987. Thalictrum cooleyi; draft stewardship abstract. The Nature Conservancy, Arlington, VA. 9 pp.
  • USFWS. 1988. Endangered Species Act Protection is Proposed for Nine Species. Endangered Species Technical Bulletin. 13, 5: 3-4.
  • USFWS. 1989. Endangered and Threatened Wildlife and Plants: Determination of Endangered Status for Thalictrum cooleyi (Cooley's meadowrue). Federal Register. Vol. 54, No. 24, February 7, 1989. Pp. 5935-593854.
  • USFWS. 1994. Cooley's Meadowrue Recovery Plan. Atlanta, Georgia: U.S. Fish and Wildlife Service. 29 pp.
  • Weakley, A. 2011. Flora of the Southern and Mid-Atlantic States. Working Draft May 2011. University of North Carolina, Chapel Hill.
  • Wilczynski, C.J. 1988. Studies on aspects of the species biology of Thalictrum cooleyi for management and conservation. University of North Carolina, Chapel Hill. 13 pp.
  • Wilcyznski, C.J. 1993. A three year study on the population dynamics of Cooley's meadowrue (Thalictrum cooleyi) at Lanier Quarry, Pender County, North Carolina. Carrboro, N.C.: The Nature Conservancy. Unpublished.

For More Information on Cooley’s meadowrue...

Species Contact:

Dale Suiter, Fish and Wildlife Biologist, 919-856-4520 ext. 18

Species profile revised on August 24, 2011.

Last Updated: August 24, 2017