meristem
mer.i.stem \'mer-*-.stem\ \.mer-*-st*-'mat-ik\ \-i-k(*-)le-\ n [Gk meristos divided (fr. merizein to divide fr. meros) + E (X-em (as in system) : a formative plant tissue usu. made up of small cells capable of dividing indefinitely and giving rise to similar cells or to cells that differentiate to produce the definitive tissues and organs - mer.i.ste.mat.ic aj