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 typically found below a branch, as branches come from axillary buds located above leaf scars.[citation needed]

photo
The leaf scar on Ailanthus altissima

Formation

Leaf scars are formed naturally, often at the end of the growing season for deciduous plants when a layer of cells called the abscissa layer forms between the petiole and stem. The abscission layer acts as a point of cleavage and the leaf breaks off leaving a cleanly shaped wound that is quickly healed over with protective cork. 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.[citation needed]

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Aesculus hippocastanum leaf scar showing seven bundle scars

See also

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.{{cite book}}: CS1 maint: location missing publisher (link)


Allikas: https://en.wikipedia.org/wiki/Leaf_scar
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