portion of plant tissue portion of meristem tissue meristem A formative plant tissue usually 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. Meristem is a plant component consisting of undifferentiated plant issue - the botanical equivalent of animal stem cells. MAT:0000006 PO:0009013 meristematic tissue James Malone BTO:0000852 A portion of plant tissue (PO:0009007) in which plant cells (PO:0009002) have retained their embryonic characteristics, or have reverted to them secondarily, and that divide to produce new cells that can undergo differentiation to form mature tissues, i.e. they have a capacity for morphogenesis and growth. MESH:D018519