1. 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; an undifferentiated cellular region in plants characterized by repeated cell division. (The meristem is a critical location for introducing colchicine when attempting to convert a diploid daylily to a tetraploid. This method converts a mature plant, whereas other methods may convert sprouting seeds.)
2. Terminal Meristem – a point of growth above the crown in a daylily where critical growth occurs – from this point crown tissue develops downward and leaf tissues develops upward.
3. Meristem tissue: Mitotically active, undifferentiated plant tissue from which all other tissues are derived.