What are meristems? Mention its characteristic features.Enumerate different kinds of meristem

Meristems are formative tissue composed of immature, undifferentiated and actively dividing cells. Main characteristic features are
1: Active mitotic division
2. Cells are isodiametric and closely packed.
3. Abundante cytoplasm and prominent nucleus.
4. Vacuoles very small or absent.
Thin, non lignified and non pectinat cellulose cell-wall