State Status: Pennsylvania Endangered (PE)
PBS Status: Pennsylvania Endangered (PE)
Global Rank: G5
State Rank: S1
Did You Know?
Despite the common name, Poa autumnalis flowers and fruits in spring.
Autumn bluegrass (Poa autumnalis) is a perennial herb with a slender hairless stem that may grow to 60cm in height. The leaves are alternately arranged, linear in shape, not toothed on the margin, parallel-veined, up to 15cm in length and 2-3mm in width, and pointed at the tip. The flowers, appearing in May and June, are individually only a few millimeters in length. They are grouped in an open branched cluster at the top of the stem, with the main lower branches of the cluster tending to be arranged in pairs or occurring singly along the stem. Despite the common name, this species flowers and fruits in spring.
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.
The PA Biological Survey (PABS) has assigned autumn bluegrass a rarity status of Endangered, based on the relatively few populations that are documented and the small state range.
Autumn Bluegrass grows in moist woods and on streambanks and slopes.
Flowers late May - June
In Pennsylvania, it has been documented historically in several southeastern counties.
Some populations are threatened by habitat loss and exotic species.
Conservation Status Map
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.