Figure legends
Figure 1. Morphological diversity of species of Ruelliaused in this study. A. R. breedlovei . B. R. macrantha . C.R. elegans . D. R. lutea . E. R. matudae . F. R. morongii . G. R. californica . H. R. hirsutoglandulosa . I.R. saccata . J. R. speciosa . K. R. longipedunculata .
Figure 2. Experimental design of crossing study, showing that both allopatric and sympatric crosses were attempted within and across major clades of Ruellia . Lines connect species pairs for which crosses were attempted (all crosses attempted bidirectionally). Dashed lines: allopatric species pairs. Solid lines: sympatric species pairs. Circles next to species names colored according to flower color. Circles are proportional to flower size (first axis of principal component analysis in Supplementary Fig. 2) and depict an overall lack of phylogenetic signal for flower color or size. Phylogeny rotated around select nodes for visual clarity.
Figure 3. Left panel : F-statistic for analyses of variance that compare interspecific distances for a given floral characteristic in sympatric vs. allopatric species pairs. High values indicate that sympatric species pairs diverge more for a given floristic characteristic relative to allopatric species pairs. Low values indicate equivalent divergences. Right panel : raw style length measurements for each species pair for which a cross was attempted; each pair represented by a vertical line and end points depict style lengths for the two species. All sympatric species pairs differ by at least 21.8 mm in style length, while 23 of 28 allopatric species pairs differ by less than 21.8 mm in style length.
Figure 4. Impacts of genetic distance, measured as interspecific phylogenetic distance in a maximum likelihood phylogeny (panels A & C) and flower shape, measured as euclidean distance in a principal components decomposition of floral shape measurements (panels B & D) on crossing success. Upper panels (A & B): allopatric species pairs. Lower panels (C & D): sympatric species pairs. Floral similarity and genetic distance significantly impacted crossing success. Covariance in flower shape and geography evident in panel D (no sympatric species pairs with a flower shape distance < 3). In C & D, note that only one sympatric cross was successful. Points staggered slightly on x-axis for visual clarity.