Stur[1008] instituted this genus for fertile fronds from the Upper Carboniferous Schatzlarer beds, including two species _Discopteris karwinensis_ and _D. Schumanni_. He described the small Sphenopteroid pinnules as characterised by disc-shaped sori made up of 70–100 sporangia attached to a hemispherical receptacle: the absence of a true annulus led him to refer the genus to the Marattiaceae. In his memoir on the coal-basin of Heraclea (Asia Minor), Zeiller[1009] instituted the species _Sphenopteris_ (_Discopteris_) _Rallii_ and figured sporangia resembling those described by Stur in the possession of a rudimentary “apical annulus.” He compared the sporangia with those of recent Osmundaceae and Marattiaceae. In the later memoir on the Upper Carboniferous and Permian plants of Blanzy and Creusot, Zeiller[1010] gives a very full and careful description of fertile specimens of _Sphenopteris_ (_Discopteris_) _cristata_, a fern originally described by Brongniart as _Pecopteris cristata_[1011]. Many of the Sphenopteroid pinnules of this quadripinnate fern frond show the form and structure of the sori with remarkable clearness in the admirable photographs reproduced in Plates I.–III. of Zeiller’s Blanzy memoir. The lobed pinnules of this species are of oval-triangular form, 5–15 mm. long and 2·5–6 mm. broad[1012]. An examination of the type-specimens of _Discopteris_ from Vienna enabled Zeiller to correct Stur’s original description of the sori: he found that the Austrian and French specimens, though specifically distinct, undoubtedly belong to one genus. The sori in _Discopteris cristata_ are globular, as in the recent genera _Cyathea_ and _Alsophila_, and frequently cover the whole face of the lamina. The individual sporangia are 0·4–0·5 mm. long and 0·15–0·2 mm. in diameter; they are exannulate, but for the annulus is substituted a group of thicker-walled and larger cells in the apical and dorsal region. The description by Stur of a hemispherical receptacle seemed to indicate an important difference between the Austrian and French species; but Zeiller found that this feature does not actually exist and that it was so described as the result of misinterpretation. Zeiller succeeded in isolating spores, 40–50 μ in diameter, from some of the sporangia of _D. cristata_ and found that they exhibited the three-rayed pattern characteristic of fern-spores and which is indicative of their formation in tetrads. The conclusion arrived at is that the genus _Discopteris_, as represented by _D. karwinensis_, _D. cristata_ etc., may be regarded as a true fern and included in the Marattiaceae. As Zeiller points out, the sori of _Discopteris_ differ from those of recent Marattiaceae in their pluriseriate construction and agree in this respect with those of the Cyatheaceae. The comparison already made[1013] between the sporangia of _D. Rallii_ and those of recent Osmundaceae holds good: the genus affords another example of a generalised type, in this case