INSECTS
for we have numerous representatives of them with us today in those lowly evergreen plants known as club mosses, whose spreading, much-branched limbs, usually trailing on the ground, are covered by rows of short, stiff leaves. The most familiar of the club mosses, though not a typical species, is the "ground pine." This humble little shrub, so much sought for Christmas decoration, still in some places carpets our woods with its sort, broad, frondlike stems. In the fall when its rich dark green so pleasingly contrasts with the somber tones of the season's dying foliage, it seems to be an expression of the vitality that has preserved the lycopod race through the millions of years which have elapsed since the days of its great ancestors. The "resurrection plant," often sold to housekeepers under false or exaggerated claims of a marvelous capacity for rejuvenation, is also a descendant of the proud lycopods of ancient times.
In our present woodlands, along the banks of streams or in other moist places, there grows also another plant that has been preserved to us from the Carboniferous forests—the common "horsetail fern," or Equisetum, that green, rough-ribbed stalk with the whorls of slender branches growing from its joints. Out equisetums are modest plants, seldom attaining a height of more than a few feet, though in South American countries some species may reach an altitude of thirty feet; but in Carboniferous times their ancestors grew to the stature of trees (Fig. 54) and measured their robust stalks with the trunks of the lycopods and giant ferns.
Aside from the numerous representatives of these several groups of plants, all more or less allied to the ferns, the Carboniferous forests contained another group of treelike plants, called Cordaites, from which the cycads of later times and out present-day maidenhair tree, or ginko, are probably descended. Then, too, there were a few representatives of a type that gave origin to out modern conifers.
[88]
