Trichomes are morphologically diverse and ecologically important structures that play a variety of roles across plant species. Although significant effort has been dedicated to elucidating trichome development and function in several (mostly model) taxa, we know relatively little about the evolutionary forces shaping trichome diversification across entire lineages. Here, we merge phylogenetic and ecological perspectives to reveal potential drivers of trichome evolution in the genus Mentzelia (Loasaceae, ca. 95 spp.), which belongs to the family that bears perhaps the most complex trichomes of any plant group. We measured microscopic trichome traits from vegetative and reproductive tissue across 40+ Mentzelia species representing wide variation in trichome morphology, geography, and habitat. We paired our dataset with the latest comprehensive phylogeny of the genus and applied phylogenetic comparative methods to test for correlations between trichome characteristics, life history traits, and bioclimatic variables. We evaluate existing adaptive and trade-off/synergism hypotheses and present initial evidence of correlations between traits. This is the first study to address longstanding questions about the adaptive value of elaborate trichomes produced by Mentzelia species and illustrate the evolutionary patterns of a complex phenotype that likely mediates interactions between plants, herbivores, mutualists, and the abiotic environment.