|Copyright: pedro anahory (anahory)
|Date Taken: 2007-01|
|Camera: Canon 30D, Sigma 28-300mm|
|Details: Tripod: Yes|
|Photo Version: Original Version|
|Date Submitted: 2007-02-12 16:50|
|[Note Guidelines] Photographer's Note|
|In botany, a leaf is an above-ground plant organ specialized for photosynthesis. For this purpose, a leaf is typically flat (laminar) and thin, to expose the cells containing chloroplast (chlorenchyma tissue, a type of parenchyma) to light over a broad area, and to allow light to penetrate fully into the tissues. Leaves are also the sites in most plants where respiration, transpiration, and guttation take place|
The veins are the vascular tissue of the leaf and are located in the spongy layer of the mesophyll. They are typical examples of pattern formation through ramification. The pattern of the veins is called venation.
The veins are made up of:
xylem, which brings water from the roots into the leaf.
phloem, which usually moves sap out, the latter containing the glucose produced by photosynthesis in the leaf.
Venation (arrangement of the veins)
Vein skeleton of a Hydrangea leafThere are two subtypes of venation, craspedodromous, where the major veins stretch up to the margin of the leaf, and camptodromous, when major veins come close to the margin, but bend before they get to it.
Feather-veined, reticulate — the veins arise pinnately from a single mid-vein and subdivide into veinlets. These, in turn, form a complicated network. This type of venation is typical for dicotyledons.
Pinnate-netted, penniribbed, penninerved, penniveined; the leaf has usually one main vein (called the mid-vein), with veinlets, smaller veins branching off laterally, usually somewhat parallel to each other; eg Malus (apples).
Three main veins originate from the base of the lamina, as in Ceanothus.
Palmate-netted, palmate-veined, fan-veined; several main veins diverge from near the leaf base where the petiole attaches, and radiate toward the edge of the leaf; e.g. most Acer (maples).
Parallel-veined, parallel-ribbed, parallel-nerved, penniparallel — veins run parallel most the length of the leaf, from the base to the apex. Commissural veins (small veins) connect the major parallel veins. Typical for most monocotyledons, such as grasses.
Dichotomous — There are no dominant bundles, with the veins forking regularly by pairs; found in Ginkgo and some pteridophytes ( in wikipedia)
I used a sigma 28-300 at 300 and a close up lens 2D
tripod and natural light
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