Sporobolus clandestinus (Biehler) Hitchc.
Family: Poaceae
hidden drop-seed, rough drop-seed, rough rush grass
[Sporobolus asper var. canovirens (Michx.) Kunth,  more...]
Sporobolus clandestinus image
from USDA Plants website  
Sporobolus clandestinus image
University of Wisconsin - Madison (WIS-VP)  
Etymology: Sporobolus: Greek spora for "seed" and ballein for "to cast forth" referring to dropping seeds at maturity
Plants: perennial grass
Conservation Status: Native
Known from a single collection made in a dry prairie in Crawford Co. in 1940.
Sporobolus clandestinus image
from USDA Plants website