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Botanical Terminology Tutorial
Leaf Arrangement
Leaf Shape
Leaf Margin
Leaf Apex
Leaf Base
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Alphabetical w/ Definitions

  1. Abaxial
    The side pointing away from the axis, usually the underside of a leaf, stem or branch.

  2. Abscission
    The loss of a structure, such as a leaf, due to a chemical process where cells form a callous layer blocking food and water causing the structure to fall off.

  3. Accessory Bud
    Buds that are not found in the axils of the leaves but are often found above or adjacent to axillary buds at a node.

  4. Acerose
    Narrow elongated leaf; Needle-shaped.

  5. Acuminate
    Sides curving concavely upward and inward then tapering to a fine point on the leaf apex.

  6. Acute
    An angle that is less than 90 with straight lines and having a point on a leaf apex.

  7. Adaxial
    The side toward the axis, usually the upper surface of a leaf, stem or branch.

  8. Alternate
    Leaves or stems situated one at a node. Leaves can alternate in a distichous pattern 180 apart along two sides of the stem, or at lesser angles around a stem.

  9. Anther
    A section of the male part of a flower containing the pollen.

  10. Apetalous
    Lacking petals.

  11. Apex
    The top; the terminal portion of a leaf; plural is apices.

  12. Apiculate
    A leaf or petal having a short slender point that is flexible.

  13. Appressed
    Firmly against another object, as a bud to a stem.

  14. Arching
    Branches of shrub (or any part of plant) that curves outward from the main body of the shrub.

  15. Asymmetric
    A plant part that has an irregular shape. (See also Oblique).

  16. Attenuate
    Leaf tissue tapers down the petiole (toward the base) to a narrow base always having some fleshy leaf on either side of the petiole.

  17. Auriculate
    Ear-lobed shaped leaf base(s) attached to petiole.

  18. Awl-shaped
    Tapering to slender stiff point; Short stiff margins narrowing to a point, often sharp and found on young Junipers.

  19. Axil
    The angled point on a stem where the leaf (or petiole) attaches to the stem.

Tutorial Terms

Leaf Apex

Leaf Arrangement

Leaf Base

Leaf Margin

Leaf Shape



2005 Gary J. Kling, Laura L. Hayden, and Joshua J. Potts University of Illinois at Urbana-Champaign.
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Notes about this tutorial.