Mark Simmons Professor and Herbarium Curator

Office: Biology 418

Phone: (970) 491-2154


Curriculum Vitae:

Google Scholar:


  • Ph.D., Cornell University
  • B.A., University of Richmond


My research program consists of two interrelated components: phylogeny and taxonomy of the flowering-plant family Celastraceae (the spindle-tree family), and conceptual aspects of molecular phylogenetics (using genomic data to reconstruct evolutionary relationships among species). The Celastraceae are a large family, primarily of lianas, shrubs, and trees with a sub-cosmopolitan distribution. Within the family, the aril has undergone tremendous diversification and ranges in form from a mucilaginous pulp to a broad wing. I am working to assess overall relationships within the family and track the pattern of aril diversification. For my conceptual research, I am working on problems such as: how alignment changes with increasing genetic distance, the trade-offs of using either nucleotide or amino acid characters, the incorporation of duplicate genes into phylogenetic analyses, the measurement of phylogenetic signal, and the use of morphological characters when entire genomes are sequenced. Molecular phylogenetics is playing an increasingly central role in biology, from inferring the diversification of multigene families, to tracking invasive species, conservation of protected species, as evidence in criminal investigations, and fighting bioterrorism.