Source : Webster's Revised Unabridged Dictionary (1913)

Acervate \A*cer"vate\, v. t. [L. acervatus, p. p. of acervare to
   heap up, fr. acervus heap.]
   To heap up. [Obs.]

Acervate \A*cer"vate\, a.
   Heaped, or growing in heaps, or closely compacted clusters.

Source : WordNet®

acervate
     adj : pertaining to a growth of fungi that forms a heaped-up mass;
           "acervate fungous sporophores"