[36] Plants having the fructification concealed, and of cellular structure only.
[37] Plants having the fructification concealed, and with vessels, or vascular tissue.
[38] Flowering plants with one cotyledon; the Endogens.
[39] Plants with naked seeds; that is, destitute of a pericarp or case.
[40] Plants with the seeds in a receptacle or pericarp, with a style and stigma.
ON THE MODE OF INVESTIGATING FOSSIL REMAINS OF VEGETABLES.
INVESTIGATION OF FOSSIL PLANTS.
The distinguished authors of the British Fossil Flora justly remark, that a few isolated, and very imperfect data, exclusively afforded by the remains of the organs of vegetation, are but too often the sole guide to the class, order, or genus of the fossil plants which the geologist has to examine; hence, in most instances, a general idea only can be obtained of the nature of the original.[41] To facilitate the study of Fossil Botany they offer some practical suggestions, which have served as the basis of the following directions for the investigation of vegetable remains, and which the previous remarks will, we trust, render intelligible.
[41] Foss. Flor. vol. I. p. xxvi.
1. The Trunk, or Stem.—Examine if the wood in a transverse section be disposed in concentric circles (as [Plate V. fig 4]): if so, it belonged to an exogenous tree: if, on the contrary, the wood appears deposited irregularly in spots ([Lign. 1, fig. 4]), then the original was endogenous. If a transverse section show remains of sinuous, unconnected layers, resembling arcs with their ends directed outwards, and of a solid structure, and imbedded among looser tissue, then it belonged to an arborescent fern; see the subjoined figures ([Lign. 2]).