It is the layer present between the endodermis and the vascular bundles. It is considered as the outer boundary of the vascular cylinder (called stele). Pericycle is seen in roots and stems; but is not found in many hydrophytes and also not in monocot stems. Pericycle may be parenchymatous as in roots or sclerenchymatous as in stems of dicot plants. In dicot plants, the sclerenchymatous pericycle may be continuous or discontinuous.
It is now considered as the component of primary phloem and the fibres are phloem fibres. The terms perivascular fibre or primary extra-xylary fibre are used to describe them.
Pericycle cells sometime contain secretory cells, laticiferous cells, canals, etc. The origin of pericycle is from apical meristem, like that of vascular tissues.
In roots, it is the seat of origin of lateral roots; and such origin is called endogenous origin. Parenchymatous pericycle serves as storage layer. In some plants, pericycle becomes meristematic and forms cambium and cork cambium.