Fig. 368.
Stigmaria ficoides, Brong. One fourth of nat. size. (Foss. Flo. 32.)
Conifers.—The coniferous trees of this period are referred to five genera; the woody structure of some of them showing that they were allied to the Araucarian division of pines, more than to any of our common European firs. Some of their trunks exceeded 44 feet in height.
Endogens.—Hitherto but few monocotyledonous plants have been discovered in the coal-strata. Most of these consist of fruits referred by some botanists to palms. The three-sided nuts, called Trigonocarpum, seven species of which are known, appear to have the best claim to rank as palms, although M. Ad. Brongniart entertains some doubt even as to their being monocotyledons.
Exogens.
The entire absence, so far as our paleontological investigations have hitherto gone, of ordinary dicotyledons or exogens in the coal measures, is most remarkable. Hence, M. Adolphe Brongniart has called this period the age of acrogens, in consequence of the vast preponderance of ferns and Lepidodendra.[316-A] Nevertheless, a forest of the period, now under consideration, may have borne a considerable resemblance to those woody regions of New Zealand, in which ferns, arborescent and herbaceous, and lycopodiums, with many coniferæ, abound.
The comparative proportion of living ferns and Araucariæ, in Norfolk Island, to all the other plants, appears to be very similar to that formerly borne by these tribes respectively in a forest of the coal-period.
I have already stated that Professor Göppert, after examining the fossil vegetables of the coal-fields of Germany, has detected, in beds of pure coal, remains of plants of every family hitherto known to occur fossil in the coal. Many seams, he remarks, are rich in Sigillaria, Lepidodendron, and Stigmaria, the latter in such abundance, as to appear to form the bulk of the coal. In some places, almost all the plants are calamites, in others ferns.[316-B]