Species Factsheets

Matelea obliqua

Oblique Milkvine

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State Status: Pennsylvania Endangered (PE)
PBS Status: Pennsylvania Endangered (PE)
Federal Status:

Global Rank: G4? rank interpretation
State Rank: S1

Did You Know?

The flowers of this species have five petals that our a maroonish color - rare specimens may be cream colored.

Matelea obliqua


Oblique milkvine (Matelea obliqua) is a herbaceous perennial vine that has hairy, twining stems. This species is a member of the milkweed family and its stems produce a milky sap if broken.

Rank Justification

Critically imperiled in the nation or state because of extreme rarity (often 5 or fewer occurrences) or because of some factor(s) such as very steep declines making it especially vulnerable to extirpation from the state.


In Pennsylvania, it grows in limestone glades, open woodlands, and thickets. This species seems to do particularly well in open woodlands created by fire.

Survey Dates

Flowers late April - October


Oblique milkvine occurs from Pennsylvania south to Georgia and west to Missouri and Mississippi.



Oblique milkvine is threatened by habitat loss through land conversion for development or habitat succession. The clearings where it grows are often transitional in nature and created by disturbance, such as fire, wind, or flooding. Over time, if these disturbances are minimized, the open habitats may become overgrown by woody or invasive species.


Maintenance of known populations and preservation of the open communities where oblique milkvine grows will be crucial to its survival. Removal of overgrowth and invasive species with the integration of fire regimes, when appropriate, will help to preserve the integrity of the sites. The management of the known sites requires long term monitoring of populations. Potential sites for restoration should be evaluated.

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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