Collaborative Research: Morphological and Molecular Systematics of the Polypodiaceae and Grammitidaceae

9807053史密斯这项研究是加州大学伯克利分校的艾伦·R·史密斯博士及其同事、科罗拉多大学的托马斯·兰克博士和堪萨斯大学的克里斯托弗·H·豪弗勒博士之间的三方合作，建立在之前蕨类研究人员成功合作的基础上。这一重大研究活动将增加我们对无籽维管植物进化和多样性的理解。这项研究的目的是探索两个高等蕨科(水龙骨科和禾本科)的近缘种的分类，它们的进化关系和地理历史，以及形态随时间的变化。1000种蕨类植物在世界各地的热带地区都有很好的代表性，除了水龙骨属本身之外，温带成员相对较少。虽然蕨类通常是古老的植物，但最近对蕨科关系的分析表明，这两个科的物种比任何其他蕨类起源得更晚。这样一个新的起源表明，这两个科的物种应该比其他更古老的群体中存在的物种比例更大，因为在其他更古老的群体中，灭绝可能已经消除了一些群体；重建这个群体的谱系历史的努力可能比更古老的派生群体的努力更成功。这项研究将考虑大量的物种，并试图从新大陆和东半球采集所有约50个已知的属和亚属的样本。至少三个叶绿体基因的形态特征和DNA序列将被用于构建这些家族进化历史的假说的分析中。定量技术将被用来推断蕨类植物的历史生物地理。

9807053 Smith This study is a three-way collaboration between Dr. Alan R. Smith at the University of California, Berkeley, and colleagues, Dr. Thomas Ranker at the University of Colorado and Dr. Christopher H. Haufler at the University of Kansas, that builds upon the previous successful collaborative efforts of fern researchers. This major research initiative will increase our understanding of the evolution and diversification of seedless vascular land plants. The goals of the proposed research are to explore groupings of related species of two advanced fern families (Polypodiaceae and Grammitidaceae), their evolutionary relationships and geographical histories, and morphological changes through time. The 1000 species of ferns are well represented in the tropical regions around the world and have relatively few temperate members, except for the genus Polypodium itself. Although ferns in general are ancient plants, recent analyses of the relationships of fern families suggest that species in these two families originated more recently than any other ferns. Such a recent origin suggests that a greater proportion of species in these two families should be extant than in other more ancient groups where extinction may have eliminated some groups; efforts to reconstruct the genealogical history of this group may be more successful than those of more ancient, derived groups. This research will consider a large number of species, and will attempt to sample all of about 50 recognized genera and subgenera from both the New World and Old World. Morphological characters and DNA sequences from at least three chloroplast genes will be used in analyses designed to construct hypotheses of the evolutionary history of these families. Quantitative techniques will be used for inferring the historical biogeography of the ferns.