Lign. 21. Cyclopteris trichomanoides; a single leaflet; nat.
Oolite, near Scarborough.
Cyclopteris (round-leaf). [Lign. 21.]—The frond is simple and entire, or but slightly lobed at the margin, and generally orbicular, or kidney-shaped: there is no midrib; the veins are numerous, equal, and dichotomous, or forked, and radiate from the base. The form and disposition of the veins resemble those of some living species of fern; the absence of a median rib, or vein, is the most striking character of this genus. The fructification is supposed to have been marginal.
FOSSIL FERNS. NEUROPTERIS.
Neuropteris (nerved-leaf). [Lign. 22].—The fronds are pinnate or bipinnate; the leaflets more or less ovate or cordiform and entire, adhering to the rachis by their centre only; veins very fine, arched, rising obliquely from the base of the leaflet; the midrib does not extend' to the apex of the leaflets, but terminates by subdividing into veins.
Lign. 22. Neuropteris acuminata; nat.
In Coal-shale, Yorkshire.
This is a very numerous genus, comprising thirty or more species, which are principally found in the coal-shale. Some of these plants bear a general resemblance to the Osmunda regalis, but differ in their essential characters; their leaflets often form the nuclei of ironstone nodules.