Virgiia young stem, TS

The Virgilia stem shown at left, is very similar to that of the TS of the young Bidens stem. The epidermis (E) , consists of a single layer of cells, and beneath this is a hypodermal layer, composed of a single row of chlorenchymatous cells.  A band of sclerenchymatous perivascular fibers (PV) just beneath the starch sheath (SS).

Vascular bundles (VB) are entirely primary.

Virgilia looks a lot like Bidens except that Bidens lacks perivascular fibers. Another example of a plant that contains a ring of conspicuous sclerenchymatous perivascular fibers exarch to the vascular bundles is Pelargonium.