The question of why some species are rare while others are common is enduring and has important implications for ecological theory, rare species conservation, and overall biodiversity. I currently am working with a team of collaborators – Carol Baskauf, Austin Peay State University; Jessica Brzyski, Seton Hill University; Mike Bonsall, University of Oxford; Jenny Cruse-Sanders, University of Georgia – on a project sponsored by the National Science Foundation (Awards #1655762, #1655521, #1655732) to address this question with a multi-faceted research approach. Our research agenda includes (1) empirical investigations that compare ecophysiological plasticity and genetic diversity within and across a suite of rare endemic and common congeneric plant species toward assessing potential acclimatory and adaptive constraints to species commonness, (2) a comprehensive and novel synthesis of existing primary literature describing trait-based comparisons of rare and common plant species to frame the empirical investigations and test their outcomes within the broader context of species rarity, and (3) the development of innovative mechanistic trait-based models that attempt to use ecologically important trait values and plasticity as derived from the empirical investigations to predict species performance and/or persistence as a broader application. These collaborative research efforts aim to provide a deeper conceptual understanding of species rarity and guidance to rare species conservation efforts. As broader impacts, this research will support student experiential learning, the targeted mentoring of students from groups underrepresented in the natural sciences and community college transfer students, and public education and engagement.