of leaf tendrils are given below: Entire leaf— Lathyrus, stipules— Smilax, terminal leaflet— Naravelia, Leaf tip— Gloriosa , Apical leaflet— Pisum, petiole— Clematis. II. Leaf hooks In some plants, leaves are modified into hook-like structures and help the plant to climb. In cat,s nail ( Bignonia unguis-cati) an elegant climber, the terminal leaflets become modified into three, very sharp, stiff and curved hooks, very much like the nails of a cat.
These hooks cling to the bark of a tree and act as organs of support for climbing. The leaf spines of Asparagus also act as hooks. Deciduous Falling at the end of growing season so that the plant (tree or shrub) is leafless in winter/ summer season. Example: Maple , Plumeria, Launea, Erythrina .
Evergreen Leaves persist throughout the year, falling regularly so that tree is never leafless. Example: Mimusops, Calophyllum . Marcescent Leaves not falling but withering on the plant as in several members of Fagaceae. Summary Flowering plants consist of two major organ systems: Underground root system and aerial shoot system.
Roots perform the functions of anchoring and absorbing nutrients from the soil. However some roots perform additional functions for which they undergo various modifications in shape, form and structure. Tap root continue the growth from the radicle which further branches into secondary roots. Adventitious roots arise from different parts of the plant other than radicle.
Stem helps to display the leaves to get maximum sunlight and positioning flowers and fruits to attract pollination and dispersal agents. Apart from the normal functions the stems are modified to perform various functions such as food storage, perennation and protection. Leaves are exogenous in origin and function as food synthesizing and gaseous exchange sites. Some leaves also perform additional functions for which they are modified in their morphology.
VI. Pitcher The leaf becomes modified into a pitcher in Nepenthes and Sarracenia . In Nepenthes the basal part of the leaf is laminar and the midrib continues as a coiled tendrillar structure. The apical part of the leaf is modified into a pitcher the mouth