The Collaborative International Dictionary of English v.0.48:

allotrophic \al`lo*troph"ic\ ([a^]l`l[-o]*tr[o^]f"[i^]k), a.
   [Gr. 'a`llos other + trophic.]
   (a) (Physiol.) Changed or modified in nutritive power by the
       process of digestion.
   (b) (Plant Physiol.) Dependent upon other organisms for
       nutrition; heterotrophic; -- said of plants unable to
       perform photosynthesis, as all saprophytes; -- opposed to
       autotrophic.
       [Webster 1913 Suppl.] Allotropical