Abstract
In the coal ball described were portions of plants that have hitherto been known from the Carboniferous of America only as impressions; they are Calamites, Sphenophyllum, Bothrodendron, and Lyginopteris. Only transverse sections of the steles of Calamites, Sphenophyllum, and Lyginopteris were found. Belonging to Bothrodendron are transverse sections of a stem tip, a megasporangium and microsporangium both attached to sporophylls and containing spores, and isolated megaspores. In the microsporangium the spores are in the tetrad stage, while in the megasporangium four megaspores were observed. The most striking feature in the comparison of Bothrodendron and Selaginella is the similarity of the two, which indeed compels the conclusion that Bothrodendron is the progenitor of the living species of Selaginella.
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