Twenty two genera containing thirty eight species and nine problematic taxa of fossil plants are described from the Lower Shihhotse Formation of the Lower Permian of Dongshan, Taiyuan, North China. They include three new genera, seven new species and two new combinations. Five genera and six species are rediagnosed. The plants described include sphenophylls, discinites, marattialeans, pecopterids, alethopterids, emplecopterids, sphenopterids, tingias, cycads, cordaites and possible conifers. Discinites dentilongii sp. nov. (Noeggerathiales) is described having disc-like sporophylls with a decurrent base. The marattialean fern Taiyuanitheca tetralinea gen. et sp. nov. has four rows of circular synangia on its pinnules. The evolution of the Marattiales is discussed. Tingia Halle and Tingiostachya Konno are rediagnosed with new morphological interpretations. Shuangnangostachya gracilis gen. et sp. nov. has spirally arranged sporophylls, each with two sporangia. This taxon is assigned to a new family. Much additional information on cycads has been gained from these assemblages,: Four species of the earliest known cycad megasporophylls are described and their taxonomy clarified. Based on the attachment of the megasporophylls of Crossozamia minor sp. nov. to an axis, new evolutionary pathways of the female cycad reproductive organs are proposed.. The later appearance of similar megasporophylls in Europe suggests that migration was from northern China westwards by dispersal of seeds in ocean currents. The associated leaf Yuania Sze and two of its species are rediagnosed". Tianbaolinia circinalis gen. et sp. nov. is considered to be an immature stage in cycad leaf development. On the evidence of the plants studied here, the climate during the early Permian in the Taiyuan area is suggested to have been warm and the humidity to have varied with local topography. The unique plants of this area reconfirm the independent nature of the Cathaysian flora.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:506618 |
| Date | January 1988 |
| Creators | Gao, Zhifeng |
| Publisher | Cardiff University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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