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[[Image:Leavessnipedale.jpg||thumb|right|200px|The leaves of a [[Beech]] tree]]

[[Image:Leavessnipedale.jpg||thumb|right|200px|The leaves of a [[Beech]] tree]]

[[Image:Leaf_1_web.jpg|thumb|right|200px|A leaf with laminar structure and pinnate venation]]

[[Image:Leaf_1_web.jpg|thumb|right|200px|A leaf with laminar structure and pinnate venation]]

In [[botany]], a '''leaf''' is an above-ground [[plant]] [[Organ (anatomy)|organ]] specialized for [[photosynthesis]]. For this purpose, a leaf is typically flat (laminar) and thin, to expose the cells containing [[chloroplast]] (chlorenchyma tissue, a type of [[parenchyma]]) to [[light]] over a broad area, and to allow light to penetrate fully into the tissues. Leaves are also the sites  

In [[botany]], a '''leaf''' is an above-ground [[plant]] [[Organ (anatomy)|organ]] specialized for [[photosynthesis]]. For this purpose, a leaf is typically flat (laminar) and thin, to expose the cells containing [[chloroplast]] (chlorenchyma tissue, a type of [[parenchyma]]) to [[light]] over a broad area, and to allow light to penetrate fully into the tissues. Leaves are also the sites in most plants where [[Respiration (physiology)|respiration]], [[transpiration]], and [[guttation]] take place. Leaves can store [[food]] and [[water]], and are modified in some plants for other purposes. The comparable structures of [[fern]]s are correctly referred to as [[frond]]s.  Leaves are prominent in the [[human]] [[diet (nutrition)|diet]] as [[leaf vegetable]]s.

 

==Leaf anatomy==

==Leaf anatomy==

A structurally complete leaf of an [[flowering plant|angiosperm]] consists of a [[petiole (botany)|petiole]] (leaf stem), a ''lamina'' (leaf blade), and [[stipule]]s (small processes located to either side of the base of the petiole). The point at which the petiole attaches to the stem is called the leaf axil. Not every species produces leaves with all of these structural parts. In some species, paired stipules are not obvious or are absent altogether. A petiole may be absent, or the blade may not be laminar (flattened). The tremendous variety shown in leaf structure (anatomy) from species to species is presented in detail below under [[#Leaf morphology|Leaf morphology]].  After a period of time, deciduous trees shead their leaves.  These leaves decompose

A structurally complete leaf of an [[flowering plant|angiosperm]] consists of a [[petiole (botany)|petiole]] (leaf stem), a ''lamina'' (leaf blade), and [[stipule]]s (small processes located to either side of the base of the petiole). The point at which the petiole attaches to the stem is called the leaf axil. Not every species produces leaves with all of these structural parts. In some species, paired stipules are not obvious or are absent altogether. A petiole may be absent, or the blade may not be laminar (flattened). The tremendous variety shown in leaf structure (anatomy) from species to species is presented in detail below under [[#Leaf morphology|Leaf morphology]].  After a period of time, deciduous trees shead their leaves.  These leaves decompose