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Oenothera sect. Calylophus is a North American group of 13 recognized taxa in the evening primrose family (Onagraceae) with an evolutionary history that may include independent origins of bee pollination, edaphic endemism, and permanent translocation heterozygosity. Like other groups that radiated relatively recently and rapidly, taxon boundaries within Oenothera sect. Calylophus have remained challenging to circumscribe. In this study, we used target enrichment, flanking noncoding regions, gene tree/species tree methods, tests for gene flow modified for target-enrichment data, and morphometric analysis to reconstruct phylogenetic hypotheses, evaluate current taxon circumscriptions, and examine character evolution in Oenothera sect. Calylophus. Because sect. Calylophus comprises a clade with a relatively restricted geographic range, we were able to extensively sample across the range of geographic, edaphic, and morphological diversity in the group. We found that the combination of exons and flanking noncoding regions led to improved support for species relationships. We reconstructed potential hybrid origins of some accessions and note that if processes such as hybridization are not taken into account, the number of inferred evolutionary transitions may be artificially inflated. We recovered strong evidence for multiple evolutionary origins of bee pollination from ancestral hawkmoth pollination, edaphic specialization on gypsum, and permanent translocation heterozygosity. This study applies newly emerging techniques alongside dense infraspecific sampling and morphological analyses to effectively reconstruct the recalcitrant history of a rapid radiation. [Gypsum endemism; Oenothera sect. Calylophus; Onagraceae; phylogenomics; pollinator shift; recent radiation; target enrichment.]

Nyctaginaceae are one of the most diverse families in core Caryophyllales. The most diagnostic character of the family is a persistent anthocarp derived from a calyx-like perianth. Anthocarp morphology is highly variable across the family, but its evolution is poorly studied. We investigate anthocarp evolution in Nyctaginaceae through extensive anatomical studies (159 species from 28 genera representing six of seven tribes) and phylogenetic character state reconstructions. We found highly diverse anthocarp anatomy across Nyctaginaceae, with most traits analysed evolving multiple times throughout the family. The representatives of three early-diverging clades of Nyctaginaceae (Leucastereae, Boldoeae and Colignonieae) possess a calyx-like anthocarp with simplified anatomy. The so-called ‘glands’ in Nyctagineae and Pisonieae are emergences, whereas wings originate by accrescence of perianth segments, elongation of the ribs and outgrowths (emergences) of anthocarp mesophyll. Anthocarp anatomy can be considered as a generic-level feature in Colignonieae, Pisonieae, Bougainvilleeae and Nyctagineae. The most dramatic transitions from perianth to anthocarp involve the shrivelling and abscission of the upper perianth part and the maintenance of the basal modified perianth portion that originated in the clade comprising Colignonieae and sister clades.