Ecology of the Early Cretaceous ferns of Northeast China

In the Early Cretaceous floras of Northeast China ferns are represented by megafossils of Dicksoniaceae, Schizaeaceae, Osmundaceae, Cladophlebis (possible Osmundaceae), Hymenophyllaceae, Adiantaceae, Gleicheniaceae and ferns with monolete spores (the latter group includes fossils sharing some characteristics with members of the modem families Athyriaceae, Dryopteridaceae, Aspleniaceae and Pteridaceae). The habit, habitat, phytogeography and climatic setting are discussed for these ferns. Acanthopteris and Coniopteris (Dicksoniaceae) are interpreted as small to large creeping rhizomatous ferns. Ruffordia goeppertii (Dunker) Seward (Schizaeaceae) was a small fern with an upright rhizome. Some Cladophlebis also had an upright rhizome., Eogonocormus and Hymenophylloides (Hymenophyllaceae) were small and delicate creeping rhizomatous ferns. Athyrium asymmetricum (Meng) Deng had large but thin and flexible fronds and may have grown in thickets. Details of habit are not known for the other ferns but several are represented by large fronds. The co-occurrence (in fine-grained sediments in coal-bearing strata) of large and/or delicate, relatively complete fronds, fertile and sterile material and rhizomes with stipes (and possible frond attachments), shows that the, majority of these ferns grew in moist habitats close to their depositional setting. Ferns such as Adiantaceae (represented only by foliage fragments) and others, represented only by dispersed spores, probably lived in different habitats. With the exceptions of Gleicheniaceae and Cladophlebis with small pinnules, these ferns occurred mainly or exclusively in the North Phytogeographic Province under a humid-temperate climate. (C) 2002 Elsevier Science B.V. All rights reserved.