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Abstract Climatic and soil features influence resources and mate availability for plants. Because of different resource/mating demands of the male and female reproductive pathways, environmental variation can drive geographic patterns of sex‐specific factors in sexually polymorphic species. Yet, the relationship between environment and sex, sexual dimorphism or sex chromosomes at the range‐wide scale is underexamined.Using ~7000 herbarium and iNaturalist specimens we generate a landscape‐scale understanding of how sex ratio and sexual dimorphism vary with geographic, climatic and soil gradients in the sexually polymorphic wild strawberry (Fragaria virginiana) and test whether these conform to predictions from theory. Then, for ~300 specimens we use genotyping of the sex‐determining region (SDR haplotypes) to reveal geographic and phenotypic patterns in sex chromosome types.Across North America, the sex ratio was hermaphrodite/male‐biased and was associated more with soil attributes than climate. Sex ratio‐environment associations matched predictions for subdioecy in the West but for gynodioecy in the East. Climatic factors correlated with sexual dimorphism in traits related to carbon acquisition (leaf size and runnering while flowering) but not mate access (petal size, flowering time). Variation in sexual dimorphism was due to one sex being more responsive to the environmental variation than the other. Specifically, leaf length in females was more responsive to variation in precipitation than in hermaphrodite/males, but the probability of runnering while flowering in hermaphrodite/males was more responsive to variation in temperature than in females. The ancestral sex chromosome type was most common overall. But the frequency of the more derived sex chromosomes varied with environmental factors that differed between East–West regions.Synthesis. A landscape‐level perspective revealed that variation in soil and climate factors can explain geospatial variation in sex ratio and sexual dimorphism in a wild strawberry. Variation in sex ratio was associated more with soil resources than climate, while variation in sexual dimorphism was the result of sex‐differential responses to climate for vegetative traits but a similar response to abiotic factors in mate access traits. Finally, sex chromosome types were associated with soil moisture and precipitation in ways that could contribute to the evolution of sex determination. 

Premise of research. Polyploidy, a major evolutionary process in flowering plants, is expected to 19 impact floral traits which can have cascading effects on pollination interactions, but this may 20 depend on selfing propensity. In a novel use of herbarium specimens, we assessed the effects of 21 polyploidy and mating system on floral traits and the pollination niche of 40 Brassicaceae 22 species. 23 Methodology. We combined data on mating system (self-compatible or self-incompatible) with 24 inferred ploidy level (polyploid or diploid) and use phylogenetically controlled analyses to 25 investigate their influence on floral traits (size and shape) and the degree of pollination 26 generalism based on the frequency and the richness of heterospecific pollen morphospecies 27 captured by stigmas. 28 Pivotal Results. Flower size (but not shape) depended on the interaction between ploidy and 29 mating system. Self-incompatible polyploid species had larger flowers than self-incompatible 30 diploids but there was no difference for self-compatible species. The breadth of pollination niche 31 (degree of generalism) was not affected by ploidy but rather strongly by mating system only. 32 Self-incompatible species had more stigmas with heterospecific pollen and higher heterospecific 33 pollen morphospecies richness per stigma than self-compatible species, regardless of their 34 ploidy. 35 Conclusions. Our results demonstrate that mating system moderated the influence of ploidy on 36 morphological features associated with pollination generalism but that response in terms of 37 heterospecific pollen captured as a proxy of pollination generalism was more variable.