Dissertation Research: Fossil History of the Saxifragaceae sensu stricto and their Woody Relatives, Cretaceous to Pleistocene

Cornell Univ - State: Awds Made Prior May 2010, Ithaca NY

Investigators

Abstract

A grant has been awarded to Dr. William Crepet and Ms. Elizabeth Hermsen of Cornell University to review the fossil history of the angiosperm (flowering plant) family Saxifragaceae (rockfoils and other ornamentals) and the related genera Ribes (currants and gooseberries) and Itea (Virginia willow). Today, these plants occur primarily in temperate, arctic, and alpine zones of the Northern Hemisphere. Published reports of fossil saxifrages will be reevaluated and new fossil saxifrages from New Jersey will be described. Some of these fossils possess details of floral structure that will allow them to be analyzed using cladistics, a mathematical technique for determining evolutionary relationships, which is of great significance as it allows for more precise analysis of these relationships than many other methods. This will aid in the attainment of the immediate goal of this project, compilation of an accurate record of fossil saxifrages. This record will be used to study questions such as when and where saxifrages originated, when they diversified, how their reproductive biology has changed over time, and how they have acheived their current geographical distribution. It will also affect our present understanding of saxifragoid relationships, especially in light of recent DNA evidence that indicates fewer plants are true saxifrages than previously thought. One of the greatest remaining evolutionary mysteries concerns the origin, relationships, and success of the angiosperms. The vital importance of this group, demonstrated by their numerical abundance and their economic, medicinal, and ecological significance, makes solving this mystery a significant priority. This project is important in the context of the overall mystery because 1) many of the processes targeted within can be generalized to historical aspects of the angiosperm proliferation and rise to dominance and 2) because the saxifrages have been considered by some earlier workers as ancestral to many more advanced flowering plant groups.