The rachis is the main axis of the pinnately compound leaf. It is the portion of the pinnately compound leaf that is attached to the petiole.
DIAGRAM: Fern Frond
A radial section is a longitudinal section of the stem that follows the radius (diameter) of the stem. It follows and is parallel to a vascular ray.
DIAGRAM: Stem Sections
The radicle is the structure that will become the root in a mature plant. When it grows out of the seed and into the soil, it grows downward.
DIAGRAM: Cotyledons / Acorn
PHOTO: Seed Cross Section / Seed Cross Section
In the vascular cambium, some cells produce the axial system and other cells produce the radial system of vascular tissue. Those vascular cambial cells that produce the radial system are known as the ray initials and those vascular cambial cells that produce the axial system are known as the fusiform initials. The fusiform initials are responsible for forming all the conducting and strengthening cells in the xylem and phloem areas of the stem and root.
The radial system is the vascular transport system in a stem that runs horizontally from the center of the stem. This is in contrast to the axial system that runs up and down the stem. The radial system carries mostly food out to the margin of the stem. In both the xylem and phloem, the radial system is made up of parenchyma cells. The ray initials are what produces the radial system.
PHOTO: Composite Flower / Composite Flower / Composite Flower
Narcissus / Narcissus
Fucus / Fucus / Fucus / Fucus / Fucus / Fucus
(as in recycling of nutrients at leaf abscission time)
The residual procambium is the procambium in the middle of the procambial strand in the dicot stem that does not differentiate. It eventually becomes the fasciscular cambial portion of the vascular cambium.
PHOTO: Root Cross Section / Root Cross Section
PHOTO: Pinus Stem Cross Section / Pinus Stem Cross Section
Various types of organic products of secretory cells in the stems of plants. In pines, it is the little globs of material in the resin ducts that give pine stems their characteristic pine odor.
Stem Cross Section /
Equisetum Gametophyte / Equisetum Gametophyte
A rhizome is a modified stem that has nodes and internodes that grows at ground level or just below ground level. It is thickened because of food storage. Stems or leaves branch off the rhizome at the nodes. Roots form by adventitious buds along the lower surface. Thus, it acts like a perennial rootstock. A good example is an iris or fern rhizome.
DIAGRAM: Microtubules / Rough Endoplasmic Reticulum
(vascular bundle arrangement)
DIAGRAM: Whole Plant / Shoot/Root
Longitudinal Section /
Root Longitudinal Section / Root Longitudinal Section
Root Longitudinal Section
DIAGRAM: Root Anatomy
PHOTO: Root Cap / Root Cap / Root Cap / Root Cap / Root Cap
Root hairs are protoplasmic extensions of the epidermal cells. They greatly expand the surface area of the root so that minerals and water are more easily absorbed.
DIAGRAM: Root Anatomy
The root-hair zone is the zone in the differentiating root tip where the final maturation and full differentiation of all the cells occurs. The prominent part of this zone is the root hairs themselves. This is where most of the water and minerals are absorbed by the root.
DIAGRAM: Root Systems
DIAGRAM: Leaf Apex / Leaf Base