. The anatomy of woody plants. Botany -- Anatomy. 262 THE ANATOMY OF WOODY PLANTS opinion now, however, is united in favor of the view that they represent the larger or main roots of lepidodendroid forms. They are, in fact, to some extent comparable to the anomalous roots found in the genus Selaginella known as rhizophores. It seems highly improbable that the type of organization presented by Stigmaria could have belonged to lepidodendrids with protostelic central cylinders. In general, the subterranean organs of plants are less frequently preserved with structural organization, since they are
. The anatomy of woody plants. Botany -- Anatomy. 262 THE ANATOMY OF WOODY PLANTS opinion now, however, is united in favor of the view that they represent the larger or main roots of lepidodendroid forms. They are, in fact, to some extent comparable to the anomalous roots found in the genus Selaginella known as rhizophores. It seems highly improbable that the type of organization presented by Stigmaria could have belonged to lepidodendrids with protostelic central cylinders. In general, the subterranean organs of plants are less frequently preserved with structural organization, since they are from the nature of things less likely to find their resting-place in open bodies of water, and this condition must usually be realized in order to insure petrifac- tion. It is accordingly probable that the genus Stigmaria, as at present defined, represents only to a limited extent the main radical organs of lepidodendroid FIG. 187.—Rootlet of Stigmaria (after Scott) The Lycopodiales as a whole are a group which reached its culmination in the Paleozoic age and from the richness of its display in earlier geological times must be regarded as extremely ancient. Although the group is almost extinct, its interest from the evolutionary standpoint is great by reason of its antiquity, which supplies valuable data for the elucidation of some of the most important problems of primitive organiza- tion in vascular plants. Clearly the group as a whole displays a reduction series in which the few types which survive under modern conditions represent, not primitive states, but the final results of a process of simplification extending through almost countless ages. Consequently it is highly inadvisable, in attempt- ing to arrive at a conception of the evolutionary significance of the group, to turn exclusive attention to modern simple forms,. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration an
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