基于对内蒙古乌达煤田下二叠统山西组4，5号煤层底板的野外工作，系统采集、鉴定植物化石18属26种，其中以华夏植物群的特有属种或常见分子占绝对优势。沉积环境及植物古生态学分析表明，5号煤底板植物群主要由Lepidodendron posthumii Jongm．and Goth．和Cathaysiodendroncf．incertum (Sze and Lee)Lee等组成，代表了三角洲平原上碎屑沼泽植被景观。4号煤底板植物群主要由成煤沼泽植物和碎屑沼泽植物混合而成，原位埋藏的Stigmaria ficoides (Sternb．)Brongn．为成煤沼泽植被类群，代表了上覆4号煤的成煤植物；由Tingia car-bonica (Schenk)Halle和 Pecopteris arborescens (Schloth．)Sternb．等组成的碎屑沼泽植被类群，代表了三角洲平原上的碎屑沼泽植被景观。综合相关研究资料和当前植物化石分析表明，煤层底板植物群主要代表了地质历史时期中的湿地植被，按照其与形成上覆煤层植物之间的关系可主要分为：上覆煤层形成初期的泥炭沼泽植物群、与成煤作用无关的碎屑沼泽植物群和两者的混合类型。底板植物群的深入研究必须要结合沉积岩石学、地层学以及埋藏学的分析。当前研究显示乌达地区早二叠世沉积时期，湿地植被组成较为稳定，其中石松类植物一直都是重要的成煤泥炭沼泽植被类型；碎屑沼泽植被与成煤沼泽植被多数情况下成分类似，仅存在种一级别的差异。

Based on the collections from the floors of coal 4 and 5 in the lower Permian Shanxi Formation, Wuda Coalfield, Inner Mongolia, 26 species within 18 genera of fossil plants have been identified. Among them, the Cathaysian elements are dominant. According to the taphonomic and palaeoecological analysis, the floor flora of coal 5 was dominated by Lepidodendron posthumii Jongm. and Goth. and Cathaysiodendron cf. incertum(Sze and Lee) Lee. This flora grew in clastic swamp in the deltaic plain. The floor flora of coal 4 was a mixed one with both clastic and peat-forming swamp vegetation. Stigmaria ficoides(Sternb.) Brongn. is autochthonous, indicating the peat-forming vegetation of coal 4 was composed of arborescent lycopsids. The Tingia carbonica(Schenk) Halle and Pecopteris arborescens(Schloth.) Sternb. assemblage represents the clastic swamp vegetation growing in the deltaic plain. Based on our synthesized analysis, coal floor floras in the Wuda Coalfield can be divided into three types: the flora that initiated formation of the peat, the clastic swamp flora which has no relationship with the overlying coal, and a flora mixed by the former two types. Characterization of these coal floor floras must take into consideration of the sedimentological interpretation of the associated lithologies, the stratigraphic sequences, and the taphonomic processes. Our current case study suggests that the wetland floras in the Wuda Coalfield were compositionally persistent during the early Permian. Arborescent lycopsids were commonly the dominant elements of the peat-forming flora. Peat-forming and clastic swamp assemblages were of taxonomic similarity with species-level differences.

中国科学院战略性先导科技专项(XDB18030404，XDPB05)；国家自然科学基金(41530101，41502006)；现代古生物学和地层学国家重点实验室自主性项目；基础性项目(20181102，20182114)联合资助