Pagiophyllum compressum (Deng and Lu) was described based on the leaf morphological and cuticular features from the Lower Cretaceous (late Aptian—early Albian) Zhonggou Formation of Jiuquan Basin, Gansu Province, North‐west China. P. compressum has helically and tightly arranged leaves appressed on the ultimate shoots, which are imbricated shapes. The epidermal cells are square or rectangular, without papillae on the periclinal walls. The stomatal apparatus is elliptic and composed of 4–7 subsidiary cells arranged in two or three longitudinal rows on the middle part of the leaves. The present specimens may be related to Araucariaceae based on the cluster analysis of morphological features. By summarizing the global distribution of the Pagiophyllum in the Late Jurassic and Cretaceous, it has been found that Pagiophyllum can live in both tropical‐equatorial hot arid belt and humid climate zone of middle and high latitudes, confirming that Pagiophyllum has an extensive habitat.
Eudicots exhibit diverse life forms and occupy a wide variety of habitats in the modern terrestrial ecosystems, and the diversification began during the Early Cretaceous; however, few Early Cretaceous fossils are preserved as multiorgan whole plants that can provide sufficient morphological characters for detailed phylogenetic assessment. Here, Fairlingtonia microgyna sp. nov. is reported from the upper Lower Cretaceous of Zhonggou Formation, Hanxia Section, Yumen City, western Gansu Province, Northwest China. The specimen is exceptionally preserved as multiorgan whole plant fossil with fibrous adventitious roots, simple and deeply dissected leaves, solitary and dehiscent capsular fruits attached to the creeping stems. As such, it was interpreted as a herbaceous eudicot. Phylogenetic analyses support a placement within the Papaveraceae, most likely in Papaveroideae, but there are obvious differences in morphological characteristics, which cannot confirm the systematic position within the Papaveraceae. Fossil records of Fairlingtonia from contemporaneous deposits (late Aptian to early Albian) in Northwest China and eastern North America provide direct evidence of the geographical radiation of Fairlingtonia on Laurasia. And the morphological characters of F. microgyna, including creeping leafy branches, fibrous adventitious roots, small and deeply dissected leaves as well as small capsular fruits with tiny seeds probably indicate that it was a colonizer of lake‐shore environments under wet and bright conditions and possessed fast‐growing and rapid propagation habitats, which allowed it to expand its geographic range with both sexual and asexual reproduction.
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