Glossary of leaf morphology

Glossary of Leaf Morphology

Glossary of leaf morphology

The study of leaf morphology is essential for understanding the diversity and function of leaves in the plant kingdom. Leaves are the primary sites of photosynthesis in most plants, and their shapes, sizes, and structures are highly variable, reflecting adaptations to different environments and functions. This glossary provides definitions and descriptions of terms commonly used to describe leaf morphology.

Basic Leaf Types

Simple Leaves

A simple leaf is a single, undivided blade. The margin of the leaf may be entire, lobed, or serrated, but the leaf is not divided into separate leaflets. Examples include the leaves of maple and oak trees.

Compound Leaves

Compound leaves are divided into multiple leaflets. Each leaflet is attached to a central rachis, and the entire structure is considered a single leaf. Compound leaves can be further classified into different types based on their arrangement:

• Pinnate: Leaflets are arranged along either side of the rachis. Examples include rose and ash leaves.
• Bipinnate: Each leaflet is further divided into smaller leaflets.
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  Glossary of leaf morphology
• Palmate: Leaflets radiate out from a single point at the end of the petiole, resembling the fingers of a hand. Examples include horse chestnut leaves.

Leaf Arrangement

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Glossary of leaf morphology

Alternate

Leaves are arranged singly at different heights along the stem, with each leaf emerging from a different node.

Opposite

Leaves are paired at each node, directly across from each other on the stem.

Whorled

Three or more leaves are attached at a single node, encircling the stem.

Leaf Margins

Entire

The leaf margin is smooth and unbroken.

Serrated

The leaf margin has small, tooth-like projections.

Lobed

The leaf margin has deep indentations, creating lobes.

Leaf Venation

Parallel Venation

Veins run parallel to each other from the base to the tip of the leaf. This is common in monocots like grasses.

Reticulate Venation

Veins form a network across the leaf. This is typical of dicots like maple and oak.

Specialized Leaf Structures

Tendrils

Modified leaves or leaflets that are used by climbing plants to attach to supports.

Spines

Modified leaves that are reduced to sharp structures, often for protection, as seen in cacti.

Bracts

Modified leaves associated with reproductive structures, often colorful, as seen in poinsettia.

Related Pages

• Leaf
• Photosynthesis
• Plant morphology
• Botany