Phylogeny of Coniferophytic Seed Plants

9527920罗斯韦尔的主要维管束植物(蕨类、裸子植物、被子植物)、针叶树及其亲密盟友(裸子植物)都有广泛的化石记录，可以追溯到至少3亿年前，并拥有丰富的矿藏，有时足以生产煤炭。尽管有丰富的材料基础，但针叶树及其近缘化石的文献记录往往很少，文献报道集中在孤立或分离的植物部分，但很少整合所有可用的材料。俄亥俄大学的古植物学家Gar Rothwell和gene Mapes正在根据他们积累的材料以及将在几个国家的博物馆藏品中研究的标本，改进对许多古代针叶树和近亲的关键分类群的全植物重建。利用从营养结构和生殖结构中收集的特征数据，研究人员可以开始解决在其化石祖先的更广泛背景下重建所有活着的针叶树、紫杉科和近亲(苏铁、银杏)的系统发育历史的长期目标。最近的分子(DNA)发现和解剖和形态特征的重新分析极大地改变了我们对几个裸子植物类群的进化关系的理解，如红豆杉属(紫杉醇的来源)和裸子植物。对许多化石属的研究，目前仅从分散的植物部分获知，将提高我们对裸子植物随时间变化的理解，并有助于建立种子植物之间血统关系的可靠假说。

9527920 Rothwell Of the major groups of vascular plants (ferns, gymnosperms, angiosperms), the conifers and their close allies (gymnosperms) have an extensive fossil record extending back at least 300 million years, and in deposits rich enough at times to produce coal. Despite this rich base of material, fossil conifers and relatives are often poorly documented, with literature reports focusing on isolated or disarticulated plant parts but rarely integrating all material available. Paleobotanists Gar Rothwell and Gene Mapes of Ohio University are working to improve whole-plant reconstructions of numerous critical taxa of ancient conifers and relatives, on the basis of material accumulated by them as well as of specimens to be studied in museum collections in several countries. With character data amassed from both vegetative and reproductive structures, the researchers can begin to address the long-term goal of reconstructing the phylogenetic history of all the living conifers, taxads, and relatives (cycads, Ginkgo) in the wider context of their fossil ancestors. Recent molecular (DNA) findings and reanalysis of anatomical and morphological features have changed dramatically our understanding of the evolutionary relationships of several gymnosperm groups like the genus Taxus (source of taxol) and the Gnetophytes. Studies of numerous fossil genera, known at present only from scattered plant parts, will improve our understanding of gymnosperm diversification through time, and contribute to robust hypotheses about lineage relationships among the seed plants.