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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. Obcordate
    Inversely cordate; heart shaped; if it is a leaf apex, the petiole attaches at the narrow end.

  2. Oblanceolate
    Inversely lanceolate; Much longer than wide with the widest point above the middle. Narrower than obovate (See also Lanceolate).

  3. Oblique
    Unequal or asymmetric especially in leaf-blade or leaf base.

  4. Oblong
    Two to four times longer than wide with nearly parallel sides.

  5. Obovate
    Inversely ovate or teardrop-shaped; leaf connected to petiole at narrow end. Wider than oblanceolate (See also Ovate).

  6. Obtuse
    Rounded leaf apex, greater than 90 at apex.

  7. Odd-pinnate
    A pinnately compound leaf that ends in a single leaflet so that there is an odd number of leaflets (See also Even-pinnate and Pinnate).

  8. Opposite
    Appear across from one another at the same node; opposite leaves may also appear decussate (each pair alternating at 90 angles at every node).

  9. Orbicular
    Circular or rounded in leaf.

  10. Oval
    Two times longer than wide with rounded ends.

  11. Ovary
    The lower portion of the female pistil that contains the ovules (See also Stygma and Style).

  12. Ovate
    Teardrop-shaped in outline and attached (to petiole) at the broad end; Wider than Lanceolate.

  13. Ovoid
    A three dimensional part that appears egg-shaped; buds, fruits, etc.

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.