This model shows the histological structures of a small part of the stem

of a corn plant in cross-section and radial longitudinal section.

The cross-section exhibits:

(i) The epidermis (pale green) covered with a cuticle as the extreme outer layer.

(ii) Thick walled mechanical tissue (yellow) inside the epidermis.

(iii) Fundamental parenchyma tissue (green)

(iv) Scattered closed vascular bundles.

Each vascular bundle has the following regions:

(a) The xylem (red/grey) on the inner side of the bundle,

and

(b) The phloem (blue) on the outer side of the bundle.

In the xylem region are found the pitted vessels (large diameter) and the annular or spirally thickened vessels (smaller diameter).

In the phloem region, there are the sieve tubes and the relatively smaller companion cells. The blue "spots" in the phloem represent the sieve plates.

The longitudinal section exhibits: the cuticle, epidermis, collenchyma, parenchyma, the sieve tubes, companion cells, the annular and spirally thickened vessels, and the air lacunae.