Phylogenetic relationship between Miocene permineralized plants and modern species.

日本北海道中北部下川群中中新世莫山鲁组中含有保存完好的硅化植物遗骸，显示出精细的组织结构。本文详细描述了在下川硅质岩中发现的硅化植物的形态解剖学特征，为紫萁科的系统发育重建提供了资料。在此基础上，对莫桑鲁组的地质、植物群和植被进行了古环境研究，根据岩性和沉积特征，将其划分为陆相沉积、河流河道、泛滥平原（化石森林遗迹）和湖泊沉积等环境。该组上部有7个硅化层（S1-S7），在S3层中获得了保存较好的近原位植物标本，组合主要由针叶和阔叶植物组成，包括两个现已灭绝的类群。大部分T ...更多信息 这些分类群可能生长在沼泽的温带环境中：蕨类植物属;薇菜属，针叶植物属;冷杉属、云杉属、铁杉属和水松属，以及被子植物属; Decodon和Alnus。对化石和现存种的解剖学特征进行了分析，为系统发育关系提供了重要数据。详细的营养器官和生殖器官的解剖结构资料，为植物的生殖发育提供了资料。即使在生殖结构未知的情况下，也可以从营养结构上得到系统发育的结果，由于薇菜分布广泛，根茎具有一些特征，因此，利用化石和现代标本可以更好地了解薇菜的系统发育。结果表明，在三迭纪就有与该种形态几乎相同的化石种被记录下来，因而该种是紫萁科中最基部的种。大的解剖变异，发现紫萁和O. claytoniana之间。它们可能属于生物学上分化的群体。少

The Middle Miocene Mosanru Formation of the Shimokawa Group in north-central Hokkaido, Japan, contains well-preserved silicified plant remains showing fine and histological structure. This paper elucidates the morphological anatomy of silicified plants found in the Shimokawa chert of the Mosanru Formation and provides the data for phylogenetic reconstruction of Osmundaceae. Furthermore, geology, flora and vegetation of the Mosanru Formation has been investigated for paleoenvironmental context.Based on lithologic and sedimentary features, this Formation is interpreted to represent some environments of deposition : terrestrial sediments, fluvial channel, flood plain (remains of fossil forests), and lacustrine sediments. The upper part of this Formation has seven silicified beds (S1-S7) and nearly in situ well-preserved plant parts are mostly obtained from the S3 bed.The assemblage is composed mainly of coniferous and broad-leaved elements that include with two now-extinct taxa. Most of t … More he taxa probably grew in a swampy temperate environment : the fern genus ; Osmunda, the conifer genera ; Abies, Picea, Tsuga and Glyptostrobus, and the angiosperm genera ; Decodon and Alnus.The quality of preservation is exquisite, and several remains allow precise study of taxonomy. Available anatomical characters of both fossil and extant species were conducted to most significant data for phylogenetic relationship. The detailed data on anatomical structure of both vegetative and reproductive organs provides the data for phylogeny. Even when the reproductive structure of above mentioned taxa is unknown, the phylogenetic results can be gained from their vegetative structures.Since Osmunda were widely distributed and possess several characteristic features in the rhizomes, their phylogeny are better understood using both fossil and modern spccies. As the result, Osmunda cinnamomea is the most basally positioned species in Osmundaceae because fossil species with almost the same morphology as this species were recorded from the Triassic. Greater anatomical variation was found between Osmunda cinnamomea and O.claytoniana. They possibly belong to biologically differentiated groups. Less