The Collaborative International Dictionary of English v.0.48:

Tremella \Tre*mel"la\, n. [NL., fr. L. tremere, to tremble: cf.
   It. tremella, F. tremelle.] (Bot.)
   A genus of gelatinous fungi found in moist grounds.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Tremella
    n 1: fungi with yellowish gelatinous sporophores having
         convolutions resembling those of the brain [syn:
         Tremella, genus Tremella]