Evolution of floral traits and mating systems under drought: A range-wide study of <em>Mimulus cardinalis</em>

Climate change is intensifying droughts across the globe, challenging species to adapt to novel conditions. While plant physiological and phenological responses to drought are well-documented, less is known about how water scarcity affects the evolution of selfing across species ranges. According to the selfing syndrome hypothesis, in environments where selfing confers a fitness advantage, selection should favour floral traits associated with increased selfing relative to outcrossing. We used a field experiment near the northern range edge of the scarlet monkeyflower (Mimulus cardinalis) to test this hypothesis both spatially (among leading-edge, central, and trailing-edge populations) and temporally (between cohorts separated by a period of historic drought). Although populations from different range positions showed genetic differentiation in some floral traits, these differences did not consistently support predictions of the selfing syndrome hypothesis. Contrary to the predictions o..., This study takes advantage of a common garden that is part of a larger resurrection experiment focused on quantifying quantitative genetic parameters and evolutionary responses to a historic period of drought across the range of M. cardinalis&nbsp;(Figure 1; Diffenbaugh et al. 2015). For this larger study, seeds were collected from six populations of M. cardinalis (two each from its northern, central, and southern range; Figure 1) in 2010 (“pre-drought” ancestors) and 2017 (“post-drought” descendants), before and after a period of historic drought, respectively (Sheth et al. 2025; Sheth &amp; Angert 2016; Vtipil &amp; Sheth 2020; Wooliver et al. 2020). Locality information for each population is reported in Sheth &amp; Angert (2016). To control for maternal and seed storage effects, plants were crossed for one generation following a nested paternal half-sibling design to allow for the estimation of quantitative genetic parameters (Sheth et al. 2025; Wooliver et al. 2020). After five wee..., # Data from: Evolution of floral traits and mating systems under drought: A range-wide study of *Mimulus cardinalis* Dataset DOI: [10.5061/dryad.vdncjsz7s](https://doi.org/10.5061/dryad.vdncjsz7s) ## Description of the data and file structure This study investigated floral trait evolution in *Mimulus cardinalis* across its range in the western United States, using a resurrection approach to compare plants originating from seeds collected before 2010 and after 2017, spanning a severe drought. In a common garden, we measured floral traits including nectar volume, sugar content, anther-stigma distance, and fecundity of self-pollinated flowers across northern-edge, central, and southern-edge populations. We hypothesized that populations from historically drier environments would shift toward selfing traits to conserve energy. Any NA represents missing data. ### Files and variables #### File: data_Dryad.csv **Description:** ##### Variables * Region: source region of the plant (sout..., ,