quack grass

from WordNet (r) 3.0 (2006)

quack grass
    n 1: European grass spreading rapidly by creeping rhizomes;
         naturalized in North America as a weed [syn: {dog grass},
         {couch grass}, {quackgrass}, {quack grass}, {quick grass},
         {witch grass}, {witchgrass}, {Agropyron repens}]

from The Collaborative International Dictionary of English v.0.48

Quitch grass \Quitch" grass`\ (kw[i^]ch" gr[.a]s`). [Properly
   quick grass, being probably so called from its vigorous
   growth, or from its tenacity of life. See {Quick}, and cf.
   {Couch grass}.] (Bot.)
   A perennial grass ({Agropyrum repens}) having long running
   rootstalks, by which it spreads rapidly and pertinaciously,
   and so becomes a troublesome weed. Also called {couch grass},
   {quack grass}, {quick grass}, {twitch grass}. See
   Illustration in Appendix.
   [1913 Webster]

from The Collaborative International Dictionary of English v.0.48

Quack grass \Quack" grass`\ (Bot.)
   See {Quitch grass}.
   [1913 Webster]