Principles of Agricultural Science – Plant

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Leaf External Parts and Types

Unit 4 – Anatomy and PhysiologyLesson 4.4 Leave It to Leaves

Principles of Agricultural Science – Plant

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Forms of Leaves

Leaves come in many shapes and forms

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Leaf Parts

Tip

Petiole

Secondary Vein

Midrib

Base

Margin

BladeCan You Name Them?

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Leaf Types

Leaves come in various sizes, colors, and physical features.

You can use physical features to distinguish among different species and varieties of plants.

Leaf features assist with classification and identification of plants.

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Physical Features of Leaves

Leaves have several physical features to examine:

Simple versus compoundShapeVenationMarginTipBaseArrangement on stem

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Simple Versus Compound

Simple Compound

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Leaf Shapes

Leaf shapes are listed on page 46 in the text

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Leaf Venation

Venation refers to how the veins are orientated within the leaf structure

Parallel

PinnatePalmate

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Leaf Margin

The edges of the leaves provide clues also

SerrateEntire Dentate

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Leaf Tip

Several styles of leaf tips exist

CuspidateMucronate Obtuse

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Leaf Base

The location of where the petiole attaches to the leaf blade is another point of reference

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Leaf Arrangement on the Stem

Arrangement of leaves on the stem provides good clues. There are arrangements for both simple and compound leaf structures.

Simple Alternate

Simple Opposite

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References

Parker, R. (2010). Plant and soil science: Fundamentals and applications. Clifton Park, NY: Delmar.