Leaf scar

A leaf scar is the mark left by a leaf after it falls off the twig. It marks the site where the petiole attached to the stem. A leaf scar is found where a plant branches.

The leaf scar on Ailanthus altissima

Formation

Leaf scars are formed naturally at the end of the growing season for deciduous plants when a layer of cells called the absciss layer forms between the petiole and stem. The absciss layer acts as a point of cleavage and the leaf breaks off leaving a cleanly shaped scar. Stipules may also leave their own scars if they are present.[1]

Bundle scars

Bundle scars are circular or barred regions within the leaf scar where bundles of vascular tissue that had connected the leaf and the stem broke off.[2] The number of bundle scars in a leaf scar is sometimes used as an identifying mark as they are often consistent across a species.

Aesculus hippocastanum leaf scar showing 7 bundle scars

References

  1. ↑ "Winter twigs". Oregon state university. Retrieved 8 November 2015.
  2. ↑ Dirr, Michael Illustrations by Bonnie Dirr (1990). Manual of woody landscape plants. (4. ed., rev. ed.). [S.l. ISBN 0-87563-344-7.
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