The genus _Rhacopteris_ (fig. 301), characteristic of the Culm flora, has been compared with _Botrychium_, but on grounds which are wholly inadequate. The species _R. paniculifera_ Stur[1095] is characterised by a stout rachis bearing two rows of laterally attached rhomboidal or subtriangular segments with a more or less deeply lobed margin and spreading veins. The rachis branches distally into two arms, and these are again symmetrically subdivided into fertile axes bearing clusters of small spherical bodies 1 mm. broad, which Stur speaks of as exannulate sporangia similar to those of _Botrychium_. He includes the species in the Ophioglossaceae. As Zeiller[1096] pertinently remarks, _Rhacopteris_ differs essentially in habit from any recent member of this family. _Rhacopteris_ also includes species characterised by leaflets deeply dissected into linear segments; an example of this form is represented by _Rhacopteris flabellata_ (Tate) recorded by Kidston[1097] from rocks of Calciferous Sandstone age in Flintshire. The specimen described by Renault[1098] from the Carboniferous rocks of Autun as _Ophioglossites antiqua_ is equally unconvincing: it consists of a carbonised fragment, 7 cm. × 1·5 cm., regarded as part of a fertile lamina characterised by a vertical series of transversely elongated slits, 7 mm. wide, some of which, on slight magnification, are seen to contain a mass of small orange-yellow granulations. The slits are compared with the surface-openings of the sunken sporangia of _Ophioglossum_, and the yellow bodies are identified as spores. The material is too imperfect to justify the use of the name _Ophioglossites_. _Noeggerathia._ This genus of uncertain position may be briefly described here, though it has little claim to recognition as a representative of the _Ophioglossales_. It is characteristic of Lower Carboniferous rocks and is compared by Stur[1099] with recent Ophioglossaceae. _Noeggerathia foliosa_ Sternb. (fig. 302) may be cited as a typical example of the genus. It consists of an axis bearing ovate leaves with numerous spreading veins. The upper part of the axis forms a spike composed of fertile leaves in the form of transversely oval bracts 2 cm. broad with a serrate edge bearing on the upper face several sporangia (3 × 4 mm.) in some of which spores have been seen (fig. 302, B, C). In another form described by Weiss[1100] the bracts bear a greater number of sporangia characterised by the presence of an arillus-like basal ring. [Illustration: FIG. 302. _Noeggerathia foliosa._ (After Stur; A, reduced.) B, Fertile leaf; C, Sporangium.]