( Nepenthes ) Phyllode ( Acacia ) Floral leaves ( Delonix ) Tendrils ( Pisum ) III. Leaf Spines and Prickles Leaves of certain plants develop spinesent structures. Either on the surface or on the margins as an adaptation to herbivory and xeric conditions. Example: Zyzypus Argemone mexicana (Prickly poppy), Solanum trilobatum .
In xerophytes such as Opuntia (Prickly pear) and Euphorbia leaves and stipules are modified into spines. Prickles are small, sharp structure which are the outgrowths from epidermal cells of stem or leaf. It helps the plant in scrambling over other plants. It is also protective against herbivory.
Example: Rosa spp. IV. Storage Leaves Some plants of saline and xerophytic habitats and members of the family Crassulaceae commonly have fleshy or swollen leaves. These succulent leaves store water, mucilage or food material.
Such storage leaves resist desiccation. Example: Aloe, Agave, Bryophyllum . V. Phyllode Phyllodes are flat, green-coloured leaf- like modifications of petioles or rachis.
The leaflets or lamina of the leaf are highly reduced or caducous. The phyllodes perform photosynthesis and other functions of leaf. Example: Acacia auriculiformis (Australian Acacia ), Parkinsonia. ii.
Bifoliolate: When there are two leaflets articulated to the petiole it is said to be bifoliolate. Example: Zornia diphylla iii. Trifoliolate: There are three leaflets articulated to the petiole it is said to be trifoliolate. Example: wood apple ( Aegle marmelos ), Clover ( Trifolium ).
iv. Quadrifoliolate: There are four leaflets articulated to the petiole it is said to be quadrifoliolate. Example: Paris quadrifolia, Marsilia v. Multifoliolate or digitate: Five or more leaflets are joined and spread like fingers from the palm, as in Cleome pentaphylla, Bombax ceiba .
. Modification of Leaf The main function of the leaf is food preparation by photosynthesis. Leaves modified to perform some specialized functions. They are described below.
I. Leaf tendrils In some plants stem is very weak and hence they have some special organs for attachment to the support. So some leaves are partially or wholly modified into tendril. Tendril is a slender wiry coiled structure which helps in climbing the support.
Some of the modification