1. Storage Leaves: Some plants of saline and xerophvtic habitats and members of the family Crassulaceae commonly have fleshy or swollen leaves. These succulent leaves store water, mucilage or food materials. Such storage leaves resist desiccation, e.g., Aloe, Agave, Bryophyllum, Kalanchoe, Sedum, etc.
2. Leaf tendrils In some plants: the whole leaf or some of its part get modified into tendril. Tendrils are long, slender, wiry and coiled climbing organs which are very sensitive to touch and coil around a support with which they come in contact. Leaf tendrils are of the following types –
- Whole leaf tendrils. In this case the entire leaf is modified into tendril, e.g., Lathyrus aphaca (wild pea). In this plant, the stipules become foliaceous to perform the function of leaves. A small bud is present in the axil of tendril.
- Leaf tip tendril. In Gloriosa superba (Glory Lily, vem. Kulhari), the leaf apices are elongated and modified into tendrils.
- Leaflet tendrils – In Pisum sativum (vern. Pea) and Lathyrus odoratus (Sweet pea), the upper few leaflets of pinnately compound leaves get modified into tendrils.
- Petiole tendrils – In some plants, the petioles become long and get modified into tendrils, e.g., Clematis (Virgin’s bower), Garden Nasturtium (Tropaeolum majus), Nepenthes, etc.
- Rachis tendril – In some plants, the tips of rachis (e.g., Lens culinaris, ver. Masur) or the entire rachis including the stalks of leaflets (e.g., Clematis) get modified into tendrils.
- Stipular tendrils – In Smilax, the free ends of adnate stipules are modified into tendrils
3. Leaf spines: In some plants, the leaves or their parts are modified into spines.Plants develop spines in order to protect themselves from grazing animals. They are also formed as means of xerophytic adaptations to reduce loss of water by transpiration.
Leaf spines are of the following types:
- In Barberry, the leaves of main stem are modified into spines.
- In Opuntia, the leaves of axillary buds are modified into spines.
- In Phoenix and Yucca, the leaf apices are modified into spines.
- In Argemone, the margin of lamina is modified into spines.
- In Ulex, the leaves are modified into spines and the branches present in the axil of them are modified into thorns.
- In Zizyphus and Acacia, stipules are modified into spines.
5. Phyllodes: 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. They are xerophvtic modifications to reduce transpiration. Examples- Australian Acacia (Acacia -auriculiformis), Parkinsonia, etc. In Parkinsonia, the leaves are bipinnatelv compound. The primary’ rachis of each leaf is short and modified into spine. The secondary rachis are modified into phyllodes. The phyllodes of Australian Acacia are pendent, vertically placed and have few stomata to reduce transpiration.
