Cretaceous and paleogene vegetation of western Canada: organismal and floristic evolution

白垩纪和古近纪见证了维管植物历史上最戏剧性的区系演变。在这段时间里，开花植物出现了，种类多样化，并上升到统治地位。丝状蕨类和松科针叶树经历了显著的进化辐射。许多其他类群，如蕨类植物和裸子植物，其多样性显著减少或类群灭绝。进化更替伴随着物种丰富度的急剧增加，与生态复杂性的增加相关。以开花植物为主的森林取代了针叶树和苏铁。蕨类植物辐射到由于植物群落复杂性增加而产生的生态位。松科针叶树多样化以支配高地和干燥生境。从苔藓植物、石松类和马尾类新种的进化和蕨类植物的爆炸性辐射可以看出，在森林地面上草本地被有显著的变化。加拿大西部的气候发生了巨大的变化，年平均气温从热带气候下降。阿尔伯塔省和不列颠哥伦比亚省是研究这些变化的最合适的地方，因为它们拥有北美最丰富的植物化石资源。阿尔伯塔省中部和南部的压缩区系可以描述许多新物种，整个植物的重建以及在其生长和沉积环境背景下的区系特征。解剖学上保存的最壮观的植物化石来自世界著名的普林斯顿燧石和温哥华岛和太平洋海岸碳酸盐海洋结核中的几个新化石来源。利用传统的解剖学、形态学和系统发育研究技术，以及三维重建、表观荧光、CLSM、扫描电镜和透射电镜等新方法，我们将从多个地点研究化石植物的进化。研究将集中在最后的前被子植物植被，早期被子植物区系和火灾的历史，水生植物区系，以及不列颠哥伦比亚省和阿尔伯塔省始新世森林的果实和种子。

The Cretaceous and Paleogene witnessed the most dramatic floristic evolution in the history of vascular plants. During this time flowering plants appeared, diversified and rose to dominance. Filicalean ferns and pinaceous conifers underwent significant evolutionary radiations. Many other groups such as pteridophytes and gymnosperms suffered significant reductions in diversity or taxa became extinct. Evolutionary turnover was accompanied by a dramatic increase in species richness, correlated with an increase in ecological complexity. Flowering plant dominated forests replaced conifers and cycads. Ferns radiated into niches produced by increased complexity of plant communities. Pinaceous conifers diversified to dominate upland and drier habitats. On the forest floor there was significant change in herbaceous ground cover as seen by the evolution of new species of bryophytes, lycopods and horsetails, and an explosive radiation of ferns. Climate of western Canada changed dramatically as mean annual temperatures decreased from tropical conditions. Alberta and BC are uniquely suited for studying these changes because they yield some of the most abundant sources of plant fossils in North America. Compression floras of central and southern Alberta allow description of many new species, whole plant reconstructions and characterization of floras in the context of their environments of growth and deposition. The most spectacular occurrences of anatomically preserved fossil plants are from the world famous Princeton Chert and several new sources of fossils in carbonate marine nodules from Vancouver Island and the Pacific coast. Using traditional techniques to study anatomy, morphology, and phylogeny, as well as newer methods for three-dimensional reconstruction, epifluorescence, CLSM, SEM, and TEM, we will investigate the evolution of fossil plants from a number of sites. Studies will center on the last pre-angiospermous vegetation, early angiospermous floras and the history of fires, aquatic floras, and fruits and seeds of Eocene forests from British Columbia and Alberta.