The Collaborative International Dictionary of English v.0.48:

accrementition \ac`cre*men*ti"tion\, n. [See accresce,
   Increment.] (Physiol.)
   The process of generation by development of blastema, or
   fission of cells, in which the new formation is in all
   respects like the individual from which it proceeds.
   [1913 Webster]