. The geological history of plants. Paleobotany; 1888. 130 THE GEOLOGICAL HISTORY OF PLANTS. species of ArchcBopteris, of the Upper and Middle Brian, are eminent as examples. This type, howeyer, scarcely extends as high as the coal-formation.* Some of the tree-ferns of the Carboniferous present yery remarkable features. Oue of these, of the genus Megaphyton, seems to have two rows of great leayes, one at each side of the stem, which was probably sustained by large bundles of aerial roots (Fig. 56). In the Carboniferous, as in the Erian, there are leaves which have been referred to ferns, but a
. The geological history of plants. Paleobotany; 1888. 130 THE GEOLOGICAL HISTORY OF PLANTS. species of ArchcBopteris, of the Upper and Middle Brian, are eminent as examples. This type, howeyer, scarcely extends as high as the coal-formation.* Some of the tree-ferns of the Carboniferous present yery remarkable features. Oue of these, of the genus Megaphyton, seems to have two rows of great leayes, one at each side of the stem, which was probably sustained by large bundles of aerial roots (Fig. 56). In the Carboniferous, as in the Erian, there are leaves which have been referred to ferns, but are subject to doubt, as possibly belonging to broad-leaved taxine trees allied to the gingko-tree of China. One of these, repre- sented in Fig. 57, has been found in the coal-formation of Sfova Scotia, and referred to the doubtful genus Noeggerathia. Fontaine has proposed for simi- lar leaves found in Virginia the new generic name Saportea. Ferns, as might be inferred from their great age, are at the present time dispersed over the whole world; but their head- quarters, and the regions to which tree-ferns are confined, are the more moist climates of the tropics and of the southern hemisphere. The coal-swamps of the northern hemisphere seem to have excelled even these favoured regions of the present world as a paradise for ferns. I have already stated that the Carboniferous consti- tutes the headquarters of the Cordaites (Fig. 58), of which a large number of sjDecies have been described, both in. Fig. 57.—Noeggerathia dispar (half natural size). * The pretty little ferns of the genus Sotrychium (moonwort), so common In American and European woods, seem to be their nearest mod- em Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Dawson, John William, Sir, 1820-1899. New York, D. Appleton and Company
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