Source : Webster's Revised Unabridged Dictionary (1913)

Mouse-ear \Mouse"-ear`\, n. (Bot.)
      (a) The forget-me-not ({Myosotis palustris}) and other
          species of the same genus.
      (b) A European species of hawkweed ({Hieracium
          Pilosella}).

   {Mouse-ear chickweed}, a name of two common species of
      chickweed ({Cerastium vulgarium}, and {C. viscosum}).

   {Mouse-ear cress}, a low cruciferous herb ({Sisymbrium
      Thaliana}). All these are low herbs with soft, oval, or
      obovate leaves, whence the name.

Source : WordNet®

mouse-ear cress
     n : a small invasive self-pollinating weed with small white
         flowers; much studied by plant geneticists; the first
         higher plant whose complete genome sequence was described
         [syn: {Arabidopsis thaliana}]