There is undoubtedly considerable confusion, which can be cleared up only by further research, as to the precise relation between _Stigmaria_ and _Stigmariopsis_ on the one hand and the different types of _Sigillariae_ on the other. The main contention, and this is the most important point, of Renault, Grand’Eury and Solms-Laubach as to the manner of formation of the aerial shoots from rhizomes and the subsequent production of forked roots and their ultimate separation from the parent rhizome is, as I believe, correct. Williamson held that _Stigmaria_ must be regarded as a true root; he found no evidence to support the view that the large rooted stem discovered by Hawshaw, Binney, and others had been originally produced from aquatic rhizomes. It must, however, be remembered that Grand’Eury’s opinion is based on evidence afforded by the exceptionally well displayed Sigillarian forests of St Étienne, on a scale such as English strata have not as yet afforded. Moreover, the absence of any parent-rhizome in association with the rooted stumps described by Williamson and by others is not a serious argument against their rhizome origin. The specimen represented in fig. 209, which was examined _in situ_ by Solms-Laubach and Grand’Eury, shows a Sigillarian stem in the Syringodendron condition bearing rows of paired parichnos scars; from the base forked and rapidly tapering arms radiate through the surrounding rock and, as shown by other specimens, these bear numerous appendages like those of the English Stigmarias. The surface-features of the arms are those of _Stigmariopsis_ and the centre of each, as seen on the broken face, is occupied by a pith-cast characterised by parallel longitudinal ridges resembling those on the medullary casts of _Calamites_. It is noteworthy that the petrified rhizome originally described by Renault as _Stigmaria flexuosa_, and afterwards identified by him as the subterranean system of _Sigillaria Brardi_, possesses a vascular cylinder composed of primary xylem strands of crescentic transverse section lining the pith; a cast of the pith, after the removal by decay of its delicate parenchymatous tissue, would exhibit the surface-features of _Stigmariopsis_. _Stigmaria flexuosa_ no doubt represents a true _Stigmariopsis_ rhizome. On the other hand, as Williamson has shown, the inner surface of the wood of _Stigmaria ficoides_ consists of a reticulum of xylem with meshes of medullary-ray tissue; a cast of such a surface presents a very different appearance from that of _Stigmariopsis_.