Species Factsheets

Thalictrum coriaceum

Thick-leaved Meadow Rue

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State Status: Pennsylvania Threatened (PT)
PBS Status: Pennsylvania Threatened (PT)
Federal Status:

Global Rank: G4 rank interpretation
State Rank: S2

Thalictrum coriaceum


Thick-leaved meadow rue (Thalictrum coriaceum), a member of the buttercup family (Ranunculaceae), grows up to 1m tall from its low woody base, or caudex. Its roots are bright yellow. Individual plants bear only male or female flowers.

Rank Justification

Imperiled in the nation or state because of rarity due to very restricted range, very few populations (often 20 or fewer), steep declines, or other factors making it very vulnerable to extirpation from the nation or state.


Thick-leaved meadow rue grows in rocky, open wooded habitats and areas with rich, moist soil in mountain or Piedmont terrain.

Survey Dates

Flower late May - June




This species is rare through much of its range, and because it requires particularly pristine forest habitat, it is very sensitive to human disturbance.


Recovery of thick-leaved meadow rue in Pennsylvania will require preservation and protection of unaltered woodlands within the plant's historical range. Removal or management of invasive competitor species and reduction of deer populations to control over-grazing will also benefit this species.

Conservation Status Map


Map Legend

NatureServe. 2017. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available https://explorer.natureserve.org.

  • NatureServe. 2018. NatureServe Explorer: An online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington, Virginia. Available at https://www.natureserve.org/explorer
  • Pennsylvania Natural Heritage Program. 2018.
  • Rhoads, A.F. and W.M. Klein, Jr. 1993. The Vascular Flora of Pennsylvania. American Philosophical Society, Philadelphia, Pennsylvania. Rhoads, A.F. and T.A. Block.
  • 2007. The Plants of Pennsylvania: An Illustrated Manual. 2nd edition. University of Pennsylvania Press, Philadelphia, Pennsylvania.
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