The Collaborative International Dictionary of English v.0.48:

Digitalis \Dig`i*ta"lis\, n. [NL.: cf. F. digitale. So named
   (according to Linn[ae]us) from its finger-shaped corolla.]
   1. (Bot.) A genus of plants of the family
      Schrophulariaceae, including the foxglove.
      [1913 Webster]

   2. (Med.) The dried leaves of the purple foxglove (Digitalis
      purpurea), formerly used in heart disease, disturbance of
      the circulation, etc. Its use has been largely replaced by
      that of the pure active ingredient, digitalin. See
      digitalin.
      [1913 Webster]

WordNet (r) 3.0 (2006):

digitalis
    n 1: a powerful cardiac stimulant obtained from foxglove [syn:
         digitalis, digitalis glycoside, digitalin]
    2: any of several plants of the genus Digitalis [syn:
       foxglove, digitalis]