On some new species of Lagenostoma, a type of pteridospermous seed from the coal measures

Abstract

The recent discoveries of the femlae fructifications of more than one memner of the Cycadofilices mark an epoch in the history of the study of this Palæozoic group, and give a valuable clue to the phylogency of the Cycads, an at one time numerous and important class of Spermophytes, Some of which still survie at the present day. It is somewhat remarkable that the discoveries of the seeds of two such diverse genera as Lyginodendron and Medullosa should have followed so closely on one another. In May, 1903, Professor Oliver and Dr. Scott showed that a petrified seed of the Gymnospermous type, previously known as Lagenostoma Lomaxi , Will. M. S., belonged to Lyginodendron , a genus of Cycadofilices possessing much divided fern-like foliage of the Sphenopteris type. In the December of the same year, Mr. Kidston described casts of a radiospermic seed in organic continuity with pinnules of Neuropteris heterophylla , a type of foliage which there as Medullosa . This seed he identified as closely similar to that first described by Gœppert and Berger as Rhabdocarpus .