Underground Stems  View Image
Rhizome Corm
It is the thick, horizontally growing underground stem.
It is profusely branched and every branch ends in a terminal bud.
Nodes and internodes are distinct
Nodes are marked by dry scale leaves, which bear buds in their axils.
Adventitious roots arise profusely from every node.
Food is stores in the stem.
Contractile roots are absent.
Ex: Ginger, turmeric		 It is thick, vertically growing underground stem axis.
It is unbranched and hence, has a single terminal bud.
Nodes are marked by scale leaves.
Adventitious roots arise from the base of nodes.
Food is stored in the stem.
Contractile roots are present in the basal nodes.
Ex: Colocasia, Crocus
Tuber Bulb
It is the swollen tip of the stolon type of underground stem branch.
Nodes are marked by the 'eyes', each of which consists of a bud, subtended by the scar left by the fallen leaf.
Contractile roots are absent.
Adventitious roots are produced from all the nodes when the tuber sprouts.
Food is stored in the stem.
Ex: Potato, Helianthus 		It is a much reduced discoidal type of underground stem.
The internodes are so much condensed that, nodes and internodes are not distinct.
Food is stored in the fleshy scale leaves.
Adventitious roots are present at the base of the reduced stem, but there is no contractile root.
There is a tunic (membranous covering) for the bulb.
There is a single terminal bud.
Ex: Onion, garlic, lilies
Sub-aerial Stems  View Image
Runner Stolon
It is a weak/creeping stem that grows horizontally on the soil surface.
It has long internodes.
It arises from an axillary bud.
Adventitious roots and aerial shoots arise from every node.
Only a mode of vegetative propagation, not of perennation.
Ex: Strawberry, grass, mint 		It is a weak, slender, lateral branch that arises from the base of the main stem.
This aerial branch arches downward and touches the ground.
The terminal bud buried in the soil gives rise to new shoot and adventitious roots.
Ex: Jasmine, blackberry
Sucker Offset
Sucker is a creeping stem that arises from the underground part of the main stem.
Non-green stem present under the soil.
Has short and thick internodes.
Adventitious roots are formed at every node that is buried in the soil.
It grows horizontally under the soil for a short distance and emerges obliquely upwards.
It is much shorter and stouter than a runner.
It gives out roots at the base before separating out from the mother plant.
Mode of propagation as well as of perennation.
Ex: Chrysanthemum		 These are the condensed form of runners, found in aquatic rosette plants.
They originate from the axil of a leaf, extend for a short distance and then produce a cluster of leaves above.
Each offset produces adventitious roots at its apex.
Axillary buds produce the next offset.
Ex: Eichhornia, Pisti.
Aerial Stems  View Image
Tendrils Thorns
These are thin, thread like spirally coiled leafless structures which twin around a neighboring object.
Ex: Terminal bud- Grapevine- Vitis, Cissus
Axillary bud- Passion flower - Cucurbita, Passiflora
Axillary branch- cucumber, pumpkin, watermelon 		These are woody, straight, pointed structures developing from the axillary buds.
They protect the plants from browsing animals.
May bear leaves, flowers or fruits in certain plants and may be branched also.
Ex: Citrus, Bougainvillea.
Phylloclades Cladode
These are fleshy, flattened and cylindrical stems that possess chlorophyll and carry out photosynthesis and store water for the plant.
They show several nodes and internodes.
The leaves are modified into spines or scales to reduce evaporation.
Commonly found in xerophytic plants.
Ex: Opuntia, Euphorbia 		A phylloclade with one or two internodes is called a cladode.
It is a short, green cylindrical or flattened branch and has a limited growth.
It resembles a leaf and arises from the axil of a much reduced scale leaf.
It may have one or two internodes only.
It helps in photosynthesis.
Ex: Asparagus, Ruscus