Notes, Exercises, Videos, Tests and Things to Remember on Structural Variation in Angiospermic leaf
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Acicular: Elongated pointed needle-shaped leaf. Eg; Pinus
Linear: Elongated, narrow flattened leaf. Eg; Grasses, Zea Hays.
Lanceolate: Elongated sword-like leaf. Eg; Nerium
Elliptic: Ellipse shaped leaf. Eg; Psidium Gwasava (Gawa)
Cordate: Hard shaped leaf or leaf with a notched base and pointed apex. Eg; Piper betel.
Obcordate: Leaf with notched apex and rounded or pointed base. Eg; Bauhinia
Ovate: Egg-shaped leaf or leaf with the broad base and narrow apex. Eg; Hibiscus
Obovate: Leaf with broad apex and narrow or pointed base. Eg; Terminalia
Oblong: Elongated rectangular leaf. Eg; Musa( Banana)
Hastate: Arrowhead-shaped leaf. Eg; upper leaf of Brassica Campestris.
Lyrate: Lyre-shaped leaf or leaf with large terminal lobe and small lateral lobes. Eg; Brassica Campestris
Acute: Leaf with a pointed apex.
Obtuse: Leaf with rounded apex.
Accuminate: Leaf with pointed apex in which extreme apex is drawn out into an elongated tale like structure.
Mucronate: Leaf with rounded or pointed apex in which short pointed outgrowth appears at the extreme tip.
Glabrous: Leaf with a smooth or non-hairy surface.
Glaucous: Leaf with the smooth and shiny surface. Eg: Rubber plant.
Pubescent: Leaf with the hairy surface. Eg: Geranium
Entire: Leaf with the smooth margin.
Repand: Leaf with slightly or lightly wavy margin.
Sinuate: Leaf with deeply wavy margin.
Serrate: Leaf with a saw - like margin in which teeth are directed towards the apex.
Serrulate: Leaf with finely serrated margin.
Dentate: Leaf with toothed margin in which teeth are outwardly directed.
Runcinate: Leaf with a saw- like margin in which teeth are directed towards the leaf base.
Herbaceous: Thin and soft textured leaf. Eg; Rose
Coriaceous: Thick firm and leathery texture. Eg; Rubber plant
Succulent: Thick and fleshy leaf which stores water in the form of mucilage. Eg; Aloe vera
Caducous: Leaves falling off much earlier in the life.
Deciduous: Leaves remaining intact at least for one season.
Persistent: Leaves remaining intact for whole life.
Cauline: Leaves arising on the main stem. Eg; Maize
Ramal: Leaves arising on the branches. Eg; All trees
Radical: Leaves arising in a cluster or in a rosette form from the reduced stem known as disc than it is known as radical leaves. Eg; Radish, Turnip.
The mode of arrangement of leaves on the node of the stem is known as phyllotaxy. It is of three types;
If single leaf arises on a node and leaves of adjacent nodes lie alternately to each other then it is known as alternate phyllotaxy. Eg; Tulsi
If a pair of leaves arise on a node and lie opposite to each other than it is known as opposite phyllotaxy. If a pair of leaves on adjacent nodes occur on the same plane than it is known as superposed opposite phyllotaxy. If a pair of leaves on adjacent node lie perpendicular to each other than it is known as decussate opposite phyllotaxy.
If a cluster of leaves arises on a node then it is known as whorled phyllotaxy.