Alternating bars of light cast a pale glow through the venation blinds on her near-white body.
The arrangement of the fibro-vascular system in the lamina constitutes the venation or nervation.
In Anomochloa there are several nearly equal ribs and in some broad-leaved grasses (Bambuseae, Pharus, Leptaspis) the venation becomes tesselated by transverse connecting veins.
The venation is useful as pointing out the number of leaves which constitute a gamosepalous calyx.
The leaf in this case is multicostate and the venation palmate.
To a distribution of veins such as this the name of reticulated or netted venation has been applied.
A leaf with only a single midrib is said to be unicostate and the venation is described as pinnate or feather-veined.
The venation is strictly parallel, the midrib usually strong, and the other ribs more slender.
It is, however, probable that a considerable group of true Ferns, allied to Marattiaceae, existed in Palaeozoic times, side by side with simpler forms. In one respect the fronds of many Palaeozoic Ferns and Pteridosperms were peculiar, namely, in the presence on their rachis, and at the base of their pinnae, of anomalous leaflets, often totally different in form and venation from the ordinary pinnules.