Leaves
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Leaf Anatomy

leaves11.jpg

leaves12.jpg

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Types of Leaves

Broad-leaved plants are usually described as having simple or compoundleaves, while narrow-leaved evergreens have needle-like, awl-shaped, or scale-like leaves. The following are examples of different leaf types.

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image leaves01.jpg Simple: not divided into leaflets; leaf composed of one blade.
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image leaves02.jpg Compound: consists of two or more leaflets.
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image leaves03.jpg Pinnately Compound: feather-like; leaflets along each side of a common axis.
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image leaves04.jpg Bipinnately Compound: primary and secondary divisions are pinnate.
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image leaves05.jpg Palmately Compound: 3 or more leaflets radiating from a common point.
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image leaves06.jpg Trifoliate: three leaflets.
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image leaves07.jpg Fascicle: cluster of needles arising from one point.
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image leaves08.jpg Single Needle
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image leaves09.jpg Scale-like
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image leaves10.jpg Awl-shaped: tapering to a slender stiff point.
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Leaf Arrangement
Leaf arrangement is the position of a leaf in reference to another leaf along the stem.

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image leaves13.jpg Opposite: leaves are directly across from each other on the stem.
Examples: Maple, Ash, Viburnum, Dogwood
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image leaves14.jpg Alternate: leaves are arranged singly at different heights and on different sides of the stem.
Examples: Elm, Hackberry, Oak, Birch
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Leaf Shapes
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image leaves15.jpg Cordate: heart-shaped.
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image leaves16.jpg Elliptic: broadest in the middle and narrower at each end.
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image leaves17.jpg Flabellate: fan-like.
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image leaves18.jpg Lanceolate: longer than wide, broadest below the middle and tapering to the apex.
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image leaves19.jpg Obovate: inversely ovate, broadest above the middle.
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image leaves20.jpg Ovate: egg-shaped, broadest below the middle.
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image leaves21.jpg Broad Ovate: wide, egg-shaped.