Dichanthelium clandestinum (L.) Gould
Family: Poaceae
deer-tongue grass
[Panicum clandestinum L.]
Dichanthelium clandestinum image
from USDA Plants Website  
Etymology: Dichanthelium: Greek dich for "two" and anthelium for "flowering" - a fair translation is "twice-flowering"
Plants: perennial grass
Conservation Status: Introduced - adventive