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Premise: Fruit type and morphology are tightly connected with angiosperm diversification. In Boraginales, the first-branching families, including Hydrophyllaceae, have one- to many-seeded capsules, whereas most of the remaining families have four-seeded indehiscent fruits. This fact argues for many-seeded capsules as the ancestral condition. However, little is known about the evolution of fruit dehiscence and seed number. The present study investigated the gynoecium and fruit development and morphology and the evolution of seed-numbers in Hydrophyllaceae., Methods: Gynoecium and fruit development and morphology were studied using scanning electron microscopy and x-ray microcomputed tomography. Ancestral character state reconstruction of seed number was performed using a broadly sampled phylogeny of Boraginales (ndhF and ITS) with an emphasis on Hydrophyllaceae., Results: Our ontogenetic studies not only demonstrate parallel developmental trajectories across Hydrophyllaceae, but also a striking diversity regarding the internal organization of the gynoecium. Ovule number appears to determine ovary structure. Many-seeded capsules are retrieved as the ancestral state of Hydrophyllaceae. At least seven transitions to fruits with (one to) four seeds and four reversals (i.e., from four- to many-seeded fruits) were reconstructed in Hydrophyllaceae., Conclusions: Several shifts in seed number from "many" to "four" and back to "many" have taken place in capsular-fruited Hydrophyllaceae, a strikingly high number considering that seed number is virtually conserved across the rest of the order. The groups with a conserved seed number of four are characterized by indehiscent schizocarps or drupes and by seeds that are integrated into mericarps. This functional integration probably acts as an evolutionary constraint to shifts in seed number., (© 2021 The Authors. American Journal of Botany published by Wiley Periodicals LLC on behalf of Botanical Society of America.)

Premise: The cactus family (Cactaceae) is a speciose lineage with an almost entirely New World distribution. The genus Eulychnia with eight currently recognized species is endemic to the Atacama and Peruvian Deserts. Here we investigated the phylogeny of this group based on a complete taxon sampling to elucidate species delimitation and biogeographic history of the genus., Methods: A family-wide Bayesian molecular clock dating based on plastid sequence data was conducted to estimate the age of Eulychnia and its divergence from its sister genus Austrocactus. A second data set obtained from genotyping by sequencing (GBS) was analyzed, using the family-wide age estimate as a secondary calibration to date the GBS phylogeny using a penalized likelihood approach. Ancestral ranges were inferred employing the dispersal extinction cladogenesis approach., Results: Our GBS phylogeny of Eulychnia was fully resolved with high support values nearly throughout the phylogeny. The split from Austrocactus occurred in the late Miocene, and Eulychnia diversified during the early Quaternary. Three lineages were retrieved: Eulychnia ritteri from Peru is sister to all Chilean species, which in turn fall into two sister clades of three and four species, respectively. Diversification in the Chilean clades started in the early Pleistocene. Eulychnia likely originated at the coastal range of its distribution and colonized inland locations several times., Conclusions: Diversification of Eulychnia during the Pleistocene coincides with long periods of hyperaridity alternated with pluvial phases. Hyperaridity caused habitat fragmentation, ultimately leading to speciation and resulting in the current allopatric distribution of taxa., (© 2021 Botanical Society of America.)