Systematics and Phylogenetics of Temperate Polypodium

利用现代技术，如染色体数目的测定、酶变异的电泳和微小形态特征的扫描电子显微镜，已经有可能相当准确地解释蕨类植物杂交物种形成的模式。然而，我们对基本的非杂交衍生物种的祖先所知相对较少。通过研究由12种温带蕨类植物组成的Polypodium vulgare复合体（Polypodium vulgare complex）的成员，本研究将发展和验证有关基本二倍体物种系统分类学的假设。在形态特征、生物地理、染色体构成、酶变异和叶绿体DNA突变等方面将积累全面的数据库。这些数据库将为详细探索这些物种之间的关系提供基础，并应使对多盆植物物种的分析能够扩展到热带生态系统。通过这些研究，我们应该深入了解这个相对未被开发的地区的多样性是如何对温带植物群的起源做出贡献的。因此，随着本研究的完成，我们应该对温带多盆植物的初级和次级物种形成途径有一个现代的综合信息。通过应用这一模型，可以为理解蕨类物种的系统分类学以及其他各种温带植物类群的系统分类学提供广义的模式和机制。

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.