A leaf scar is the mark left by a

leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

after it falls off the twig. It marks the site where the petiole attached to the

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

. A leaf scar is typically found below a branch as branches come from

axillary bud The axillary bud (or lateral bud) is an embryonic or organogenic shoot located in the axil of a leaf. Each bud has the potential to form shoots, and may be specialized in producing either vegetative shoots (stems and branches) or reproductive sh ...

s located above leaf scars. 20150228Ailanthus altissima1

Formation

Leaf scars are formed naturally, often at the end of the growing season for

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...

plants when a layer of cells called the abscissa layer forms between the petiole and stem. The

abscission Abscission () is the shedding of various parts of an organism, such as a plant dropping a leaf, fruit, flower, or seed. In zoology, abscission is the intentional shedding of a body part, such as the shedding of a claw, husk, or the autotomy of a ...

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.

Stipule In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole). Stipules are considered part of the anatomy of the leaf of a typical flowering plant, although in many speci ...

s may also leave their own scars if they are present.

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. The number of bundle scars in a leaf scar is sometimes used as an identifying mark as they are often consistent across a species. 20150304Aesculus hippocastanum1

References

Plant morphology {{botany-stub