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

这项研究是加州大学伯克利分校的Alan R. Smith博士及其同事，科罗拉多大学的Thomas Ranker博士和堪萨斯大学的Christopher H. Haufler博士的三方合作，建立在之前蕨类研究人员成功合作的基础上。这项重大的研究计划将增加我们对无籽维管陆地植物的进化和多样化的理解。本研究旨在探讨水蛭科（Polypodiaceae）和禾本科（Grammitidaceae）两个高等蕨类科的近缘种归属、进化关系、地理历史以及形态变化。蕨类植物有1000多种，分布在世界各地的热带地区，温带地区的蕨类植物相对较少。虽然蕨类植物一般都是古老的植物，但最近对蕨类植物科关系的分析表明，这两个科的物种比任何其他蕨类植物的起源都要晚。这样一个最近的起源表明，这两个科中存在的物种比例应该大于其他更古老的类群，在这些类群中，灭绝可能已经消灭了一些类群；重建这一群体的系谱历史的努力可能比那些更古老的衍生群体更成功。这项研究将考虑大量的物种，并将尝试从新世界和旧大陆采集所有约50个已知的属和亚属。形态学特征和至少三个叶绿体基因的DNA序列将用于分析这些家族的进化历史。定量技术将用于推断蕨类植物的历史生物地理学。

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.