The undifferentiated plant tissue from which new cells are formed, as that at the tip of a stem or root.
Undifferentiated plant tissue, as the growing tips of roots and stems, the cambium, etc., consisting of actively growing and dividing cells that give rise to various permanent tissues.
Plant tissue whose cells actively divide to form new tissues that cause the plant to grow. The originally undifferentiated cells of the meristem can produce specialized cells to form the tissues of roots, leaves, and other plant parts. The meristem includes the growing tips of roots and stems (the apical meristems) and the tissue layer known as cambium.
Greek meristosdivided (frommerizeinto divide) (frommerisdivision(s)mer-2 in Indo-European roots) -em (as in xylem) (phloem)
The separation of layers in the apical meristem of the root is usually very much more obvious than in that of the stem.
The branches of the stem arise by multiplication of the cells 01 the epidermis and cortex at a given spot, giving rise to a protuber ance, at the end of which an apical meristem is established.
If this division occurs by means of a localized secondary meristem connecting the cambial layers of adjacent bundles, an inlerfascicular is formed in addition to the fascicular cambium.
An ordinary cambium is scarcely ever found in the Monocotyledons, but in certain woody forms a secondary meristem is formed outside the primary bundles, and gives rise externally to a little secondary cortex, and internally to a secondary parenchyma in which are developed numerous zones of additional bundles, usually of concentric structure, with phloem surrounded by xylem.
In nearly all plants which produce secondary vascular tissues by means of a cambium there is another layer of secondary meristem arising externally to, but in quite the same fashion as, Ph II