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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). The edge of the leaf may be regular or irregular, and may be smooth or have hair, bristles, or spines.
Duration of leaves: Deciduous – leaves are shed after the growing season. Evergreen – leaves are retained throughout the year, sometimes for several years. Fugacious – lasting for a short time: soon falling away from the parent plant. Marcescent – dead leaves, calyx, or petals are persistent and retained. Persistent – see Marcescence ...
A plant that loses all of its leaves only briefly before growing new ones, so that it is leafless for only a short time, e.g. approximately two weeks. bristle A straight, stiff hair (smooth or with minute teeth); the upper part of an awn (when the latter is bent and has a lower, stouter, and usually twisted part, called the column ).
180° (or 1 ⁄ 2): two leaves in one circle (alternate leaves) 120° (or 1 ⁄ 3): three leaves in one circle; 144° (or 2 ⁄ 5): five leaves in two gyres; 135° (or 3 ⁄ 8): eight leaves in three gyres. Most divergence angles are related to the sequence of Fibonacci numbers F n. This sequence begins 1, 1, 2, 3, 5, 8, 13; each term is the ...
Leaf of Pyrus calleryana with petiole. In botany, the petiole (/ ˈ p iː t i. oʊ l /) is the stalk that attaches the leaf blade to the stem. [1]: 87 [2]: 171 It is able to twist the leaf to face the sun, producing a characteristic foliage arrangement (spacing of blades), and also optimizing its exposure to sunlight.
The seeds are sown from December to January in small plots (almacigas) sheltered from the sun, and the young plants when at 40 to 60 cm (16 to 24 in) in height are placed in final planting holes (aspi), or if the ground is level, in furrows (uachos) in carefully weeded soil. The plants thrive best in hot, damp and humid locations, such as the ...
The basal leaves are green, cordate, more or less elongated and pointed and always with rounded and often sharply defined white or pale green patches. The upper surface of the leaves has tiny bumps and it is quite hairy. The leaves of this host plant are eaten by the caterpillars of the moth Ethmia pusiella. In spring, the plant produces small ...
Acacia fasciculifera seedling in the transitional stage between pinnate leaves and phyllodes. The leaves of acacias are compound pinnate in general. In some species, however, more especially in the Australian and Pacific Islands species, the leaflets are suppressed, and the leaf-stalks become vertically flattened in order to serve the purpose of leaves.