What are the divisions of sub-aerial stems??

Subaerial modifications of Stem:In subaerial modifications, the stem is partly aerial and partly underground. Short aerial branches and adventitious roots develop at the nodes. Detachment of entire branch or a node can develop into a new plant. The plants are commonly known as creepers and their subaerial stem modifications meant for vegetative propagation.
1. Runner:It is a creeping stem with long internodes, running horizontally on the soil surface. Runner arises from an axillary bud. Runners break off and grow into individual plants. Examples – Lawn grass, Oxalis.2. Sucker:It arises from the basal, underground part of the main stem. It grows horizontally for a distance under the soil and then emerges obliquely upwards. It develops a leafy shoot and adventitious roots before separating from the mother plant. The common sucker-bearing plants are Chrysanthemum, banana, Mint, etc.

3. Stolon:It is a weak lateral branch that arises from the base of main stem. After growing aerially for some time it bends downwards to touch the ground, where its terminal bud gives rise to a new shoot and adventitious roots. The common stolon bearing plants are strawberry.

4. Offset:It is a short runner with one internode long. It originates from leaf axil, grows as a short horizontal branch. It produces a rosette of leaves above and adventitious roots below. Offsets art generally found in aquatic plants like Pistia (water lettuce), Eichorrnia (water hyacinth), etc.