rice grass
/ˈrʌɪs ˌɡrɑːs/ /ˈrʌɪs ˌɡras/noun
1Any of several barnyard grasses (genus Echinochloa); especially shama millet, E. colona (formerly Panicum colonum).
2 Australian and NZ. Any of various grasses; especially (a) the marsh grass Leersia hexandra; (b) (chiefly with distinguishing word) any of several grasses of the genera Microlaena and Tetrarrhena (both sometimes included in the genus Ehrharta), especially (more fully meadow rice grass, weeping rice grass) Microlaena stipoides, which grows in tufts from creeping rhizomes in semi-shaded ground (also called weeping grass).
3 US. Any of various perennial grasses of the genus Oryzopsis; especially (more fully Indian rice grass) O. hymenoides, which grows in clumps in semi-arid regions of the western United States.
4Any of several cordgrasses (genus Spartina) of salt marshes and estuaries, especially the hybrid S.x townsendii, of southern England and western France.
Origin
Mid 18th century; earliest use found in Griffith Hughes (1707–1750). From rice + grass.