The evolution of autogamy is hypothesized to correlate with a reduction in traits associated with pollinator attraction. Floral scent represents a complex trait with ecological consequences and strong potential for rapid evolution. However, few studies have broadly tested the hypothesis that floral scent emissions differ between selfing and outcrossing lineages. Here, we present a glimpse into the complexity of floral volatiles across a monophyletic clade of Nyctaginaceae (Abronia and Tripterocalyx) and provide the first phylogenetically replicated study of floral scent emission in the context of mating system evolution. We measured floral volatile and morphological traits in a common garden including 24 of around 30 taxa in this largely self-incompatible, monophyletic clade. Across two independent transitions to autogamy, lineages experienced parallel reductions in total floral volatiles, and transitions to smaller and fewer flowers. We also found that species which close their flowers during the day, characteristic of moth pollination, emit distinct volatile profiles. Our results may support pollination syndromes within this clade, provide macroevolutionary snapshots of transitions between mating systems and suggest a predictable, multi-trait reduction of investment in autogamous lineages.