Ravennagrass (
Ripidium ravennae (L.) Trinius) was noticed by several sharp observers in the mid-Atlantic region who reported it in 2009, in time for it to be included in the 4th edition of the Plant Invaders book as one of the "Plants to Watch" (p. 130). If you spot this non-native plant outside of landscaped areas, please report your observation to 
MAEDN.
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| Ravennagrass, Ripidium ravennae photo by  The Nature Conservancy Archive, Bugwood.org
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The Mid-Atlantic Early Detection Network or MAEDN is powered by 
EDDMapS.
Other images for Ravennagrass can be found at 
Invasive.org.