In the section in Volume +ii.+ devoted to the genus _Pecopteris_ reference was made to the species _P. Pluckeneti_[439], further treatment being deferred until other Pteridosperms had been described. The fern-like fronds originally described by Schlotheim as _Filicites Pluckeneti_[440] and afterwards transferred by Brongniart and other authors to _Pecopteris_[441] are now recognised as the leaves of a Pteridosperm. Some doubt has been expressed as to the specific identity of the specimens figured by Schlotheim and Brongniart respectively, but Potonié’s examination of the type-specimen of the earlier author convinced him that Brongniart’s leaves were correctly named. The large fronds of _Pecopteris Pluckeneti_ are characterised by the bifurcation of the principal axis which bears opposite pairs of bi- or tri-pinnate branches and in the angles of the bifurcations of the rachis undeveloped buds occur on prolongations of the axis, a habit recalling recent species of _Gleichenia_[442] (figs. 225 and 226, vol. +ii.+). The variation in the form of the pinnules is shown in fig. 442, A, which represents both the apical portion and parts of pinnae 10 cm. lower on the rachis of a large leaf from the Coal Measures of Radstock. The species is characteristic of the Upper Coal Measures and is recorded also from Permian strata. In 1883 Sterzel adopted for this species the generic name _Dicksonites_ because of the occurrence of shallow circular cups at the end of the lowest lateral vein on some of the pinnules which he believed to be sori of the Cyatheaceous type. The cups have an involute margin and occasionally a small scar in the centre (fig. 442, B). Stur[443] declined to accept Sterzel’s evidence as satisfactory and suggested a fungal origin for the sorus-like impressions, a view, as Sterzel objected, that is rendered improbable by the constant position of the single cups on several pinnules. The nature of Sterzel’s ‘sori’ has not been demonstrated: it is suggested by Grand’Eury[444] that they mark the position of microsporangia. Some seed-bearing specimens in Dr Kidston’s collection show cups, like those figured by Sterzel, on pinnules from which the seeds have fallen, and it is not improbable that they are the scars of seeds. In 1905 Grand’Eury published a description and photographs of specimens of _P. Pluckeneti_ from the St Étienne coal-field showing hundreds of well-preserved seeds, many of them attached to pinnules characterised by a very slightly reduced lamina. Some fronds were found to be entirely fertile, while others bore both sterile and fertile pinnae. The smallest seeds, 5 mm. long and 3 mm. broad, were found at the tips of unexpanded leaves: the mature seeds, only slightly larger, agree in their broadly oval form and narrow marginal ‘wing’ with small examples of _Samaropsis_[445]. The seeds were figured by Grand’Eury[446] in an earlier work as _Carpolithes granulatus_. They are believed to