<P> A meristem is the tissue in most plants containing undifferentiated cells (meristematic cells), found in zones of the plant where growth can take place . </P> <P> Meristematic cells give rise to various organs of the plant and keep the plant growing . There are three types of meristematic tissues: apical (at the tips), intercalary (at middle) and lateral (at the sides). </P> <P> There are two types of apical meristem tissue: shoot apical meristem (SAM), which gives rise to organs like the leaves and flowers, and root apical meristem (RAM), which provides the meristematic cells for future root growth . SAM and RAM cells divide rapidly and are considered indeterminate, in that they do not possess any defined end status . In that sense, the meristematic cells are frequently compared to the stem cells in animals, which have an analogous behavior and function . </P> <P> The term meristem was first used in 1858 by Karl Wilhelm von Nägeli (1817--1891) in his book Beiträge zur Wissenschaftlichen Botanik ("Contributions to Scientific Botany"). It is derived from the Greek word merizein (μερίζειν), meaning to divide, in recognition of its inherent function . </P>

What type of animal cell is similar to plant meristematic