A new Permian gnetalean cone as fossil evidence for supporting current molecular phylogeny

Annals of Botany
Zi-Qiang Wang

Abstract

The order Gnetales has been the central focus of controversy in seed plant phylogeny. Traditional treatment of morphology supports the anthophyte hypothesis with Gnetales sister to angiosperms but current molecular data reject this hypothesis. A new fossil gnetalean cone, Palaeognetaleana auspicia gen. et sp. nov., is reported from the Upper Permian in North China, and its phylogenic implications are considered. Samples of cones from the upper part of the Upper Permian redbeds of Baode section, northwestern Shanxi Province, China, were examined. The cone is characterized by its unusual nature of reproduction that combines features of post-Triassic gnetaleans and some of the Palaeozoic conifers. It is made up of a number of imbricate axillary units, each simply formed by an ovule and a subtending bract, which may be comparable with the axillary seed-scale complex of some of the Palaeozoic conifer cones. The cone exhibits at least a partially bisexual character that appears to have pollen sacs with monosulcate ribbed pollen grains and sessile, asymmetric, and radiospermic ovules. The ovule has an integument of three envelopes: an outer one of pointed scales; a middle sclerified one; and an inner cuticle that extends upward into a...Continue Reading

Citations

Jul 7, 2011·The New Phytologist·John T ClarkePhilip C J Donoghue
Jan 31, 2018·Nature Plants·Michael S Barker
Jan 20, 2018·Science Advances·Timo J B van EldijkBas van de Schootbrugge
May 22, 2017·Journal of Plant Research·Gabriela G PueblaMercedes B Prámparo
Jan 27, 2009·Molecular Phylogenetics and Evolution·Chung-Shien WuShu-Miaw Chaw

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