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.
Ravennagrass, Ripidium ravennae
photo by The Nature Conservancy Archive, Bugwood.org
The Mid-Atlantic Early Detection Network or MAEDN is powered by EDDMapS.
Other images for Ravennagrass can be found at Invasive.org.