State Status: Pennsylvania Endangered (PE)
PBS Status: Pennsylvania Endangered (PE)
Global Rank: G5
State Rank: S2
Did You Know?
The common names for this species, sawgrass and twig rush, are misleading since it is actually a sedge, not a grass or rush.
Twig-rush (Cladium mariscoides) is a perennial grass-like herb with upright stems that grow up to 1m tall. The leaves are linear, rough along the edges, and about 3mm wide. The individual flowers, appearing in summer, are minute and are grouped in small, brown spikelets that are covered by spirally arranged scales. The spikelets are grouped into 6mm heads which are displayed in a narrow cluster. The fruits are about three mm long and acorn-shaped.
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.
The PA Biological Survey (PABS) considers twig-rush to be a species of special concern, based on the few occurrences that have been recently confirmed and its wetland habitat. It has a PA legal rarity status and a PABS suggested rarity status of Endangered. About fifteen populations are currently known in the state.
It grows in quaking bogs, marshes, fens, and along shorelines of lakes and ponds.
Flowers late June - early August; fruits late July - September
In Pennsylvania, it has been documented historically in scattered locations, particularly in the glaciated northwestern and northeastern counties.
The viability of populations of twig-rush and its habitat may be enhanced by creating buffers around wetlands, controlling invasive species, and protecting the natural hydrology surrounding wetlands.
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.