Stems and branches are the above ground parts of the plant axis and bear leaves, buds, flowers at nodes. The in­ternal structure of stem at the nodes and at internodes differ slightly due to the above reasons.

In general, a stem is characterised by the following internal organisations:

(i) Epidermis is with or without hairs but when epidermal hairs are present, they are multicellu­lar or unicellular.

(ii) Hypodermis is present either in a continuous or discontinuous manner.


(iii) Vascular bundles are conjoint, collateral or bicollateral, and endarch with centrifugal develop­ment of xylem.