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Chart illustrating leaf morphology terms. The following terms are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (that is, the leaf blade or 'lamina' is undivided) or compound (that is, the leaf blade is divided into two or more leaflets). [1]
A leaflet (occasionally called foliole) in botany is a leaf-like part of a compound leaf. [1] Though it resembles an entire leaf, a leaflet is not borne on a main plant stem or branch, as a leaf is, but rather on a petiole or a branch of the leaf. [2] Compound leaves are common in many plant families and they differ widely in morphology. [3]
paripinnate: pinnately compound leaves in which leaflets are borne in pairs along the rachis without a single terminal leaflet; also called "even-pinnate". imparipinnate: pinnately compound leaves in which there is a lone terminal leaflet rather than a terminal pair of leaflets; also called "odd-pinnate".
The leaves are pinnate (in the form of bird feathers, pinnae), with a central leaf stalk from which parallel "ribs" emerge from each side of the stalk, perpendicular to it. The leaves are typically either compound (with leaflets emerging from the leaf stalk as "ribs"), or have edges ( margins ) so deeply cut ( incised ) so as to appear compound.
The primary leaf or leaves of a plant embryo which upon germination develops into the seed-leaf or the first set of leaves. craspedodromous Pinnate venation in which the secondary veins terminate at the margin s, often as teeth. crateriform In the shape of a saucer or shallow cup; hemispherical or more shallow. cremnophyte
In a frond which is pinnate (feather-shaped), each leafy segment of the blade is called a pinna (plural pinnae), the stalk bearing the pinna is termed a petiolule, and the main vein or mid-rib of the pinna is referred to as a costa (plural costae). [6] If a frond is divided once into pinnae, the frond is called once pinnate.
In peltate leaves, the petiole attaches to the blade inside the blade margin. In some Acacia species, such as the koa tree , the petioles are expanded or broadened and function like leaf blades; these are called phyllodes. There may or may not be normal pinnate leaves at the tip of the phyllode.
Leaf morphology: Shape, margin and venation. Leaf Parts: – A complete leaf is composed of a blade, petiole, and stipules, but in many plants one or more might be lacking or highly modified. Blade – see lamina. Lamina – the flat and laterally-expanded portion of a leaf blade. Leaflet – a separate blade, among others, of a compound leaf