Underground Modifications of StemSome underground STEMS are modified for food storage and to survive under unfavourable conditions. Some underground stem modifications are:RhizomeThese are non-green with distinct nodes and internodes. There are auxiliary as WELL as apical buds. These are brownish in colour. The common types of rhizomes are fleshy due to the storage of food material. It also contains terminal buds. E.g., gingerThe rhizome rootstock GROWS vertically upwards instead of horizontal. BANANA and Alocasia indica are some examples of the rhizome.Bulb Many fleshy scale leaves are present. The base of the bulb consists of a cluster of adventitious roots. E.g., onion, garlic.The bulb may be tunicated or scaley. A sheath of dry membranous scale leaves covers the tunicated bulb. A scaley bulb contains no tunic.CormThis condensed form of the stem grows in the vertical direction. It is spherical in shape with a flattened base. It has distinct nodes and internodes. Adventitious roots are present either at the base or all over the body. The auxiliary buds are present on the sides. E.g., Colocasia.TuberIt is a fleshy part of the plant which stores food. Potato is the most common tuber largely used as food. The lower part of the potato gets covered by the earth where the adventitious branches grow. It is covered with a number of depressions called “eye” and each eye represents a node. It does not contain adventitious roots. These are largely used as food and grow very slowly.Aerial Modifications of StemThe stems are modified into aerial forms to perform important functions such as climbing, food storage, vegetative propagation, and PROTECTION. The stem modifications are as follows:Stem TendrilsThe stem gets modified into a threadlike leafless structure called tendrils. These are meant for climbing. These may not necessarily contain a branch. Stem tendrils may be:Axillary: E.g., PassifloraExtra-axillary: E.g., LuffaApical bud: E.g., GrapevineFloral Bud: E.g., AntigononThorns These are pointed, hard structures which may or may not bear leaves, branches and flowers. The terminal bud gets modified into thorns. Thorns are used as defence organs and help to check transpiration. E.g., BouganvilleaThorns can be distinguished from spines and prickles as they are deep-seated with vascular connections. Prickles are superficial outgrowths on the plant. Spines are the modified plant organs.PhyllocladesThese are leaves modified into scales or spines to check transpiration. This is done by controlling the growth of the leaves. These are fleshy, green, and take part in photosynthesis. This modification is seen in xerophytic plants and stores water. E.g., Opuntia. It consists of fleshy internodes and the leaves are modified into spines or small scaly leaves.CladodesIt is a type of phylloclade which consists of only one internode. These are cylindrical but non-fleshy. These help in photosynthesis. Eg., Asparagus. In this, the leaves are modified into prickles.BulbilsThese are modified axillary vegetative or floral buds meant for food storage. They undergo vegetative propagation to form a new plant. E.g., Dioscorea. In this, the bulbils are condensed auxiliary buds.Thalamus It is the axis of the flower and contains the flower organs such as calyx, corolla, androecium, and gynoecium. Silene exhibits clear nodes and internodes.Explanation:Please mark my answer as the brainliest!!!!!!And give it a star!!!