Renaultia.
This name was proposed by Zeiller[1018] for Upper Carboniferous fertile pinnae of the Sphenopteroid type, bearing ovoid sporangia either singly or in marginal groups of 2 to 5 at the ends of the veins. The appearance of the apical cells occasionally suggests the presence of a rudimentary annulus. Kidston has recorded this type of fructification in Britain[1019]. Stur describes fertile pinnules of the same type under the generic name Hapalopteris[1020].
Zeilleria.
This genus was founded by Kidston[1021] for fertile pinnae of a very delicate fern, Zeilleria delicatula (Sternb.) characterised by filiform ultimate segments bearing an indusium-like body, spherical when immature and splitting at maturity into four small valves. Kidston, in his earlier paper, compared the species with recent Hymenophyllaceae. In the same genus he includes Z. avoldensis[1022] (Stur) assigned by Stur to Calymmatotheca, a genus described by some authors as characterised by groups of radially elongated sporangia at the tips of the pinnules; these supposed sporangia are now known to be the valves of an indusium-like organ or cupule, as Stur asserted. There can be little doubt that the fertile fronds placed in Calymmatotheca and in Zeilleria were borne by Pteridosperms.
Urnatopteris.
The Upper Carboniferous fronds of a delicate Sphenopteris habit, to which this name was assigned by Kidston[1023], were described by him as Eusphenopteris tenella (Brongn.)[1024] and compared with Hymenophyllaceae; subsequently Kidston expressed the opinion that Urnatopteris may be a Marattiaceous fern, as Williamson[1025] believed; he has since suggested that the sporangia are the microsporangia of a Pteridosperm[1026]. The sterile and fertile pinnae differ in the absence of a lamina in the latter. The sporangia (or microsporangia) are characterised by a poricidal dehiscence.
The records from strata higher in the geological series than the Permian, disregarding many of doubtful value, afford ample testimony to the existence of Marattiaceae in Upper Triassic and Rhaetic floras.
Marattiopsis.
The generic name Danaeopsis was applied by Heer[1027] to an Upper Triassic fern, previously described by Presl as Taeniopteris marantacea. A splendid specimen from the Keuper of Stuttgart is figured in Schimper’s Atlas[1028] showing the pinnate habit of the frond and the broadly linear segments, 25 cm. × 3·5 cm., bearing rows of contiguous sporangia. The large pinnules have a strong midrib giving off curved and forked lateral veins. Presl’s species may most appropriately be included in the genus Marattiopsis. A specimen of M. marantacea described by Leuthardt[1029] as Danaeopsis marantacea from the Upper Trias of Basel shows a peculiarity in the venation; the lateral veins often fork near their origin, as noticed by other authors, but each vein forks a second time near the edge of the lamina and the two arms converge, forming a series of intramarginal loops ([fig. 265], B).