XXIII.—On the Internal Structure of Sigillaria elegans of Brongniart's “Histoire des végétaux fossiles”

Abstract

Before giving a description of the specimen which forms the subject of this communication, it seems desirable that a brief summary of the literature dealing with the internal structure of Sigillaria, and some general remarks on the classification of the genus, should be given.More for the purpose of convenience than on scientific grounds, the genus Sigillaria is usually divided into four groups. These groups were originally supposed by their founders to be of generic value, but experience has shown that the characters on which they were founded are more or less common to all four divisions, and in some cases the distinctive divisional characters even occur on the same specimen.