ROACHES AND OTHER ANCIENT INSECTS
are to an abundance of hard-wood, leafy trees and shrubs, and a multitude of flowering plants. None of these forms of vegetation had yet appeared.
Much of the undergrowth of the Carboniferous swamps was composed of fernlike plants, many of which were, indeed, true ferns, and perhaps the ancestors of our modern brackens. Some of these ancient ferns grew to a great size, and rose above the rest in treelike forms, attaining a height of sixty feet and more, to branch out in a feathery crown of huge spreading fronds. Another group of plants characteristic of the Carboniferous flora comprised the seed ferns, so named because, while closely resembling ferns in general appearance, they differed from true ferns in that they bore seeds instead of spores. The seed ferns were mostly small plants with delicate, ornate leaves, and they have left no descendants to modern times.
Along with the numerous ferns and seed ferns in the Carboniferous swamps, there were gigantic club mosses, or lycopods, which, ascending to a height sometimes of much more than a hundred feet, were the conspicuous big trees in the forests of their day (Fig. 54). These lycopods had long, cylindrical trunks covered with small scales arranged in regular spiral rows. Some had thick branching limbs starting from the upper part of the trunk and closely beset with stiff, sharp-pointed leaves; others bore at the top of the trunk a great cluster of long slender leaves, giving them somewhat the aspect of a gigantic variety of our present-day yucca, or Spanish bayonet. The bases of the larger trees expanded to a diameter of three or four feet, and were supported on huge spreading underground branches from which issued the roots—a device, perhaps, that gave them an ample foundation in the soft mud of the swamps in which they grew.
The Carboniferous lycopods furnished most of our coal, and then, in later times, their places were taken by other types of vegetation. But their race is not yet extinct,
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