The Collaborative International Dictionary of English v.0.48:

Acervate \A*cer"vate\, v. t. [L. acervatus, p. p. of acervare to
   heap up, fr. acervus heap.]
   To heap up. [Obs.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Acervate \A*cer"vate\, a.
   Heaped, or growing in heaps, or closely compacted clusters.
   [1913 Webster]

WordNet (r) 3.0 (2006):

acervate
    adj 1: pertaining to a growth of fungi that forms a heaped-up
           mass; "acervate fungous sporophores"