The stem bears buds, which may be either TERMINAL or AXILLARY.
Buds are the young embryonic shoot, yet to develop. Buds normally occurs at the apex of the stem or in the axil of a leaf.
Buds have compressed axis in which the internodes are not elongated and the young leaves are closely crowded. When the sizes of buds increase the internodes elongate and the leaves spread out.
Majority of the buds are protected by one to several bud scales. When the bud tissue starts growing these bud scales fall-off.
(1) TERMINAL (APICAL) BUD: Terminal buds occur at twig tips. When a bud is located at the apex (tip) of the main stem or branch it is called terminal bud or apical bud.
(2) AXILLARY BUD: These buds are located in the axil. When a bud arises in the axil of a leaf, it is known as axillary bud.
The axillary buds of stems later may develop into branches, modified into pointed thorns or may contain tissues to develop into flowers.
Unlike axillary buds, terminal buds do not grow into side branches.
ADVENTITIOUS BUD: In many plants, buds develop in positions other than the stems. Such buds are known as adventitious buds. We may see these buds growing in internodes, on roots or along the roots and near the surface of the ground.