The Collaborative International Dictionary of English v.0.48:

acrogenic \acrogenic\ adj.
   1. 1 pertaining to acrogens, flowerless plants (ferns or
      mosses) in which growth occurs only at the tip of the main
      stem.

   Syn: acrogenous
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

acrogenic
    adj 1: pertaining to flowerless plants (ferns or mosses) in
           which growth occurs only at the tip of the main stem
           [syn: acrogenic, acrogenous]