DOI: 10.5061/dryad.24bb47s
title: Data from: Convergent evolution in floral morphology in a plant ring species, the Caribbean Euphorbia tithymaloides

description: Premise of the Study: Ring species have long fascinated evolutionary
 biologists for their potential insights into lineage divergence and
 speciation across space. Few studies have investigated the potential for
 convergent or parallel evolution along the diverging fronts of ring
 species. We investigate a potential case of parallel floral variation in
 the Caribbean spurge Euphorbia tithymaloides, the only plant system with
 molecular support as a ring species. The terminal populations of each
 front, despite being the most divergent, exhibit such similar floral
 traits that were originally considered each other closest relative.
 Methods: We evaluate convergence in floral and leaf traits in relation to
 geography across 95 populations spanning the distribution of E.
 tithymaloides. We also re-analyze available genetic data (from previous
 phylogenetic analyses) in an explicitly spatial framework. Key Results:
 Floral morphology appears to have shifted in a convergent fashion along
 both geographic fronts of E. tithymaloides, resulting in shorter and more
 compact inflorescences in Antillean populations compared to the typical
 elongate ‘slipper-like’ cyathia characteristic of the area of origin.
 Patterns of spatial genetic variation were more consistent with a
 two-fronted invasion of the Caribbean than a simpler model of isolation by
 distance. Conclusions: Floral divergence in E. tithymaloides is consistent
 with convergent evolution along the two fronts of a ring species. We
 outline several non-mutually exclusive mechanisms that could be driving
 patterns in morphology, including shifts toward generalized pollination
 with reduced reliance on hummingbirds, shifts in floral structure closely
 matching available hummingbird bill traits, and shifts toward increased
 selfing. Please be aware that if you ask to have your user record removed,
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description: alignments_2genes_EtithymaloidesAlignments for SGN and G3PDH genes for E. tihtymaloidesmorphological_data_EtithymaloidesData for cyathia and leaf traits, including image identifiers from where data were collected.population_info_EtithymaloidesPopulation data, including country, distance to the Anegada Passage, and codes linking to tip and morphological data.images_tithy_MEXU_082817Images of herbarium vouchers used to measure morphological traits.images_tithy_ivcolls_dryadImages of field collections used to measure cyathial and leaf traits of E. tithymaloidesimages_tithy_ivcolls_A.zipimages_tithy_ivcolls_B_bycoll1Images from field collections from where cyathia and leaf traits were measured.images_tithy_ivcolls_C_bycoll2Images from field collections from where cyathia and leaf traits were measured.images_tithy_ivcolls_D_bycoll3Images from field collections from where cyathia and leaf traits were measured.images_tithy_ivcolls_E_crImages from field collections from where cyathia and leaf traits were measured.images_tithy_ivcolls_F_guatImages from field collections from where cyathia and leaf traits were measured.images_tithy_ivcolls_G_ex08Images from field collections from where cyathia and leaf traits were measured.images_tithy_ivcolls_H_ven1Images from field collections from where cyathia and leaf traits were measured.images_tithy_ivcolls_I_ven2Images from field collections from where cyathia and leaf traits were measured.images_tithy_ivcolls_J_ven3Images from field collections from where cyathia and leaf traits were measured.