The Collaborative International Dictionary of English v.0.48:

Dryadella \Dryadella\ n.
   a genus of plants comprising tropical American species
   usually placed in the genus Masdevallia; they are very
   dwarf plants having short tufted and usually unifoliate stems
   with usually solitary flowers.

   Syn: genus Dryadella.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

Dryadella
    n 1: comprises tropical American species usually placed in genus
         Masdevallia: very dwarf plants having short tufted and
         usually unifoliate stems with usually solitary flowers
         [syn: Dryadella, genus Dryadella]