Systematics and Phylogenetics of Temperate Polypodium

利用现代技术，如染色体数目测定、酶变异体电泳和扫描电子显微镜的细微形态特征，已经有可能相当准确地解释蕨类植物的杂交物种形成模式。然而，我们对基本的、非杂交衍生物种的祖先知之甚少。通过研究由大约12种温带蕨类植物组成的水龙骨属复合体的成员，拟议的研究将发展和检验关于基本二倍体物种系统学的假设。将积累关于形态特征、生物地理学、染色体组成、酶变异性和叶绿体DNA突变的全面数据库。这些数据库将为详细探讨这些物种之间的关系提供基础，并应使对水龙骨属物种的分析能够扩展到热带生态系统。通过这些研究，我们应该深入了解世界上这个相对未被开发的地区的多样性如何有助于我们温带植物区系的起源。因此，随着拟议研究的完成，我们应该有一个关于温带水生植物初级和次级物种形成途径的现代综合信息。通过应用这个模型，可以概括描述多样性模式的模式和机制，以了解蕨类物种的系统学，也许还可以理解其他温带植物群的系统学。

Using modern technologies such as determination of chromosome numbers, electrophoresis of enzyme variants, and scanning electron microscopy of minute morphological features, it has been possible to explicate patterns of hybrid speciation in ferns quite accurately. We know comparatively little, however, about the ancestry of the basic, non-hybrid-derived species. By studying members of the Polypodium vulgare complex, a group of about twelve species of temperate ferns, the proposed research will develop and test hypotheses about the systematics of basic diploid species. Comprehensive data bases will be accumulated on morphological features, biogeography, chromosome constitution, enzyme variability, and chloroplast DNA mutations. These data bases will provide the basis for a detailed exploration of the relationships among these species and should enable the analysis of Polypodium species to be extended into the tropical ecosystems. Through these studies we should gain insights on how the diversity in this relatively unexplored part of the world has contributed to the origin of our temperate flora. Thus, with the completion of the proposed research, we should have a modern synthesis of information on the primary and secondary speciation pathways in temperate Polypodium. By applying this model, modes and mechanisms that characterize patterns of diversity may be generalized for understanding the systematics of fern species and perhaps for a variety of other temperate plant groups.