Audrey Dignan Spencer (MSES, 2019) recently published the first chapter of her thesis research in the Journal of the Torrey Botanical Society.  Therein, she and thesis research advisor Professor Emeritus Leo P Bruederle describe geographical variation for a taxonomically important morphological trait that has long confused North American botanists who have puzzled over the taxonomy of Physocarpus opulifolius, the common ninebark. Precise taxonomic circumscription relies on observable and reliable morphological characters and research such as this is critical for downstream ecological and systematics research.  Audrey appreciates the support she received from the departments of Integrative Biology and Geography and Environmental Sciences, as well as the Kathryn Kalmbach Herbarium at Denver Botanic Gardens