nit-grass
/ˈnɪtɡrɑːs/ /ˈnɪtɡras/Botany
noun
A grass of the genus Gastridium; especially G. ventricosum, which has shiny swollen glumes resembling nits (more fully awned nit-grass).
Origin
Mid 19th century; earliest use found in William Hooker (1785–1865), botanist. From nit + grass.