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Summary The tree of life is riddled with reticulate evolutionary histories, and some clades, such as the eastern standingPhlox, appear to be hotspots of hybridization. In this group, there are two cases of reinforcement and nine hypothesized hybrid species. Given their historical importance in our understanding of plant speciation, the relationships between these taxa and the role of hybridization in their diversification require genomic validation.Using phylogenomic analyses, we resolve the evolutionary relationships of the eastern standingPhloxand evaluate hypotheses about whether and how hybridization and gene flow played a role in their diversification.Our results provide novel resolution of the phylogenetic relationships in this group, including paraphyly across some taxa. We identify gene flow during one case of reinforcement and find genomic support for a hybrid lineage underlying one of the five hypothesized homoploid hybrid speciation events. Additionally, we estimate the ancestries of four allotetraploid hybrid species.Our results are consistent with hybridization contributing to diverse evolutionary outcomes within this group; although, not as extensively as previously hypothesized. This study demonstrates the importance of phylogenomics in evaluating hypothesized evolutionary histories of non‐model systems and adds to the growing support of interspecific genetic exchange in the generation of biodiversity. 

Abstract PremiseA central goal of pollination biology is to connect plants with the identity of their pollinator(s). While predictions based on floral syndrome traits are extremely useful, direct observation can reveal further details of a species' pollination biology. The wildflowerPhlox drummondiihas a floral syndrome consistent with pollination by Lepidoptera. We tested this prediction using empirical data. MethodsWe observed each step of pollination inP. drummondii. First, we observed 55.5 h of floral visitation across the species range. We used temporal pollinator exclusion to determine the contribution of diurnal and nocturnal pollination to reproductive output. We then quantifiedP. drummondiipollen transfer by the dominant floral visitor,Battus philenor. Finally, we tested the effect ofB. philenorvisitation onP. drummondiireproduction by quantifying fruit set following single pollinator visits. ResultsBattus philenoris the primary pollinator ofP. drummondii. Pollination is largely diurnal, and we observed a variety of lepidopteran visitors during the diurnal period. However,B. philenorwas the most frequent visitor, representing 88.5% of all observed visits. Our results show thatB. philenoris an extremely common visitor and also an effective pollinator by demonstrating that individuals transfer pollen between flowers and that a single visit can elicit fruit set. ConclusionsOur data are consistent with the prediction of lepidopteran pollination and further reveal a single butterfly species,B. philenor, as the primary pollinator. Our study demonstrates the importance of empirical pollinator observations, adds to our understanding of pollination mechanics, and offers a specific case study of butterfly pollination. 

Summary Effective insect pollination requires appropriate responses to internal and external environmental cues in both the plant and the pollinator.Helianthus annuus, a highly outcrossing species, is marked for its uniform eastward orientation of mature pseudanthia, or capitula. Here we investigate how this orientation affects floral microclimate and the consequent effects on plant and pollinator interactions and reproductive fitness.We artificially manipulated sunflower capitulum orientation and temperature in both field and controlled conditions and assessed flower physiology, pollinator visits, seed traits and siring success.East‐facing capitula were found to have earlier style elongation, pollen presentation and pollinator visits compared with capitula manipulated to face west. East‐facing capitula also sired more offspring than west‐facing capitula and under some conditions produced heavier and better‐filled seeds. Local ambient temperature change on the capitulum was found to be a key factor regulating the timing of style elongation, pollen emergence and pollinator visits.These results indicate that eastward capitulum orientation helps to control daily rhythms in floral temperature, with direct consequences on the timing of style elongation and pollen emergence, pollinator visitation, and plant fitness.