The Collaborative International Dictionary of English v.0.48:
Doob grass \Doob" grass`\ [Hind. d?b.] (Bot.) A perennial, creeping grass (Cynodon dactylon), highly prized, in Hindostan, as food for cattle, and acclimated in the United States. [Written also doub grass.] [1913 Webster]The Collaborative International Dictionary of English v.0.48:
Doub grass \Doub" grass`\ (d[=oo]b" gr[.a]s).(Bot.) Doob grass. [1913 Webster]