Systematics, Floral Structure and Reproductive Biology of Mid-Cretaceous Magnoliid Angiosperms

开花植物是植物中最大的一类，被子植物大约有50万种。除了多样性之外，被子植物对人类的经济也有巨大的重要性。被子植物也是许多或大多数陆地生态系统的主要组成部分，在所有非针叶林陆地生物群落中占主导地位。可以理解的是，植物学家一直对发展模型和推断这一高度重要群体的起源和辐射很感兴趣。在过去的二十年里，技术（分子系统学和分支学）已经发展到可以对开花植物的起源问题和该群体的系统发育模型进行严格的科学研究。因此，关于被子植物树基部的系统发育关系的假设现在是可用的。被子植物的起源和初级辐射发生在白垩纪；然而，白垩纪的化石记录相对较差。克兰建议研究白垩纪被子植物化石的多样性，这些被子植物化石位于现在的美国东部和葡萄牙。这些样本包括花、花粉、果实和种子，所有这些样本都对了解和分类开花植物具有诊断价值。他打算通过将化石形式整合到当前的关系模型中来探索它们之间的关系，并对这些模型进行测试。基于这些发现，他建议对最早被子植物的古生态和传粉进行探索。将酌情发展新的关系模式。已经收藏的标本将通过电子显微镜和光学显微镜进行检查。本文的研究将对我们对被子植物及其进化史的认识产生有益的影响。反过来，这应该刺激使用分子和分支学方法的更多研究。

The flowering plants comprise the largest group of plants, Angiospermae with approximately 500,000 species. In addition to sheer diversity, the angiosperms are of tremendous economic importance to humans. Angiosperms are also major elements of many or most terrestrial ecosystems, and dominate all non-coniferous terrestrial biomes. Understandably, botanists have been interested in developing models and inferences concerning the origin and radiation of this highly significant group. Within the past two decades techniques (molecular systematics and cladistics) have become available to permit rigorous scientific inquiry into the problem of the origin of the flowering plants and phylogenetic models of the group. Accordingly hypotheses of phylogenetic relationships are now available for the base of the angiosperm tree. The origin and primary radiation of the angiosperms was in the Cretaceous; however, the fossil records from the Cretaceous are relatively poor. Crane proposes to examine the diversity of fossil angiosperms in Cretaceous deposits in what is now the eastern United States and Portugal. These samples include flowers, pollen, fruits, and seed, all of which are of diagnostic utility in understanding and classifying flowering plants. He intends to explore relationships among the fossil forms by integrating them into the current models of relationships and to test those models. Based on these findings, he proposes to explore the paleoecology and and pollination of the earliest angiosperms. New models of relationships will be developed as appropriate. Examination of the specimens, which are already in collections, will be via electron and light microscopy. The described research will have a salutary effect on our understanding of the angiosperms and their evolutionary history. This, in turn, should stimulate additional research using molecular and cladistic approaches.