Stems


Vascular bundle (amphiphloic) from the rhizome of Osmunda ferns.
Another Osmunda vascular bundle view showing the darkly stained endodermis.
Osmunda vascular bundle surrounded by ring of thick-walled fibers.

Vascular bundle (plectostele) from a Lycopodium stem.
Selaginella stem with close-up of vascular bundle.
Another view of a vascular bundle from Selaginella.

Vascular bundle from Polypodium fern.
Amphiphloic vascular bundle in Polypodium.
Psilotum cross-section.

Psilotum stem - cross-section showing stele (protostele).
Closer view of one pole of the xylem tissue in a Psilotum stem.
Psilotum stem - longitudinal section through stele showing secondary wall structure in tracheids and fibers.

Another Psilotum stem in longitudinal view showing the range of cells from fibers at the right to early tracheids at left.
Pine apical meristem.
Pine stem tip.

Vascular trace near the tip of a pine stem.
Close-up of pine vascular trace shown in image to the left.  From left to right in this trace would be protoxylem, procambium, and protophloem.
Radial-longitudinal view of xylem in a pine stem with primary xylem left of center.

Longitudinal section through the tip of a pine stem bud.
Close-up of part of the pine stem bud shown at left.  The procambium leading into one of the leaf primordia is visible from the elongated cells and their nuclei.
Back from the pine stem tip, the procambium has produced primary xylem and phloem.

Vascular bundle in Helianthus stem.
Close-up of Helianthus vascular bundle showing the group of phloem fibers capping the bundle.
Cross-section of Ranunculus stem with insets showing vascular bundles.

Wide view of a Helianthus stem showing epidermis, cortex, vascular bundles and pith.  Note collenchyma just inside the epidermis (see closer view to right).
Helianthus stem vascular bundle.
Vascular bundle in Lilium stem.

Outer region of a Lilium stem showing thick-walled cells of the cortex.
One-year-old pine stem (cross-section).
One-year-old pine stem (cross-section) showing xylem and phloem tissues.

Yucca stem cross-section.
Yucca vascular bundles - one in cross-section, one in longitudinal section.
Yucca stem longitudinal section showing secondary wall structure of xylem elements.