Ningxia Centre Back Under The Riverside Two Nodal Class Cones And The Late Carboniferous To The In Situ Spore Research

In the Yaogou section of Xiaheyan, Zhongwei, Ningxia Hui Autonomous Region, the deposits from the late Early Carboniferous Tsingyuan Formation to Late Carboniferous Taiyuan Formation (lower member) are completely developed. The tectonic structure is simple. Animal and plant fossils are abundant, and the age of the stratigraphic units has been clearly defined. The sphenopsid fructifications described in this paper are collected from Bed8of the Namurian Hongtuwa Formation. In situ spores of the fructifications have been analyzed. The morphology of the strobili, together with the characteristics of the in situ spores has enhanced the accuracy of the identification of the taxa. It is indicated that the character of the in situ spores is highly significant for the identification of poorly preserved sphenopsid strobili.Two new species of Calomostachys and Palaeostachya are proposed. The in situ spores of Calamostachys are identified. The method of in situ spore analysis has been presented in detail.The strobili of Calamostachys xiaheyanensis sp. nov.(pl.1, figs.1-13, pl.2, figs.10-13) are cylindrical, with the upper part tapering gradually towards a pointed apex. They are at least155mm long,8-15mm wide, and possess a18-28mm incomplete peduncle. The sporophylls are of5-7mm in length, arising from the nodes. The in situ microspores Calamospora xiaheyanensis sp. nov.(pl.3, figs.1-12, pl.4, figs.1-12) are usually subcircular to circular. The maximal diameter of the microspores is about55μm. The trilete rays extend to1/3to1/2of the radius. There is no obvious structure in the contact area. The thickness of the sporoderm is approximately1μm.Palaeostachya xiaheyanense sp. nov.(pl.2, figs.1-9) stribili are cylindrical in shape. They are at least80mm long and18-20mm wide on the impression, distiactly ribbed and altaneted at the nodes, the internodes are very short, only4mm long. The sporangia ablong—ovate in shape attaching singly, and directly at the nodes in an axillary position,0.3mm wide on the compression diameter. The number of the sporangia in the each node might expected6. The bracts leaving the axis in an almost perpendicular direction, and then turning upwards nearly parallel with the axis, the vertically distal parts of bracts meacuring about thrice the length of the internodes. The strobilus—bearing specimen belongs certainly to the reproductive organ of the Calamites. The axllery attachment of the sporangia suggests that our specimen may belong to Palaeostachya. Attempts to isolate the spores (in situ microspores) from sporangia yield on good results.