Leaf Trace

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leaf trace

[′lēf ‚trās]
A section of the vascular bundle that leads from the stele to the base of the leaf.

Leaf Trace


a vascular bundle in the stem of a plant that directly connects the stem with a leaf. Depending on the plant species, one or several leaf traces may be associated with each leaf. From the base of the leaf down through the stem, the leaf trace passes through several internodes that correspond to the particular leaf arrangement and encounters and merges with other leaf traces that lead to previously developed leaves. Thus, a unified network of conducting bundles is formed in the shoot. Some vascular plants, such as lycopods, have small simple leaves (microphylls) with weak leaf traces that do not reach the conducting cylinder of the stem. The macrophyllous leaves of the Polypodiaceae, Gymnospermae, and Angiospermae have large leaf traces and are characterized by numerous leaf gaps.

References in periodicals archive ?
Axes showing endarch maturation and a sympodial vasculature have been classified as Cordaixylon, while those with mesarch leaf traces and a non-sympodial vasculature, as seen in the Joggins specimen (Fig.
The Parenchymatous cortex is differentiated into an inner zone with leaf traces running obliquely and an outer zone with girdling traces.
The parenchymatous cortex has idioblasts, abundant mucilage ducts, and oblique, semigirdling leaf traces [ILLUSTRATION FOR FIGURE 5C OMITTED].
Examples of such structural synapomorphies for the extant Cycadales are girdling leaf traces, an inverted omega pattern of vascular bundle arrangement in petiole and cataphyll bases, protoxylem poles changing from endarch in the stem to exarch in the leaf traces, a primary thickening meristem, a contractile taproot, and ageotropic, coralloid, lateral roots (Stevenson, 1990b; Norstog & Nicholls, 1998).