Dissertation Research: Evolutionary origins of gypsophily in Nama (Boraginaceae)

University Of Texas At Austin, Austin TX

Investigators

Abstract

Gypsum deposits, characterized by high rates of species endemism and distinctive plant communities, are under threat of habitat destruction from commercial mining operations. Gypsum endemism (gypsophily) has arisen independently in many different genera in arid regions around the world, however, in most cases it is not clear whether there are single or multiple origins within genera containing numerous gypsum-adapted species. This study will use independent nuclear and chloroplast molecular datasets to reconstruct the evolutionary history of Nama (Boraginaceae), a New World genus comprising 53 species, including 11 gypsophiles, to test hypotheses regarding the origins of gypsophily and biogeographic patterns within the genus. Morphological observations will be used to examine character evolution in Nama, prepare diagnostic keys to all species, and provide data for a taxonomic revision of a group of closely related Nama gypsophiles. The results of this research will add significantly to the knowledge of the evolutionary history of gypsum endemics in particular and the evolution of substrate-based endemism in general. Information gained through this study also has potential applications to biodiversity conservation efforts. To make biodiversity data on Nama available to researchers in the United States and Mexico, duplicate voucher specimens will be deposited at herbaria in both countries. Diagnostic keys to all species in English and Spanish, allowing specimens to be identified in the field or herbarium, will be published online and in print to be of maximum value to amateur and professional botanists. Opportunities to share the results of this research with the general public exist through the Lady Bird Johnson Wildflower Center in Austin, an Organized Research Unit of the University of Texas.