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Advances in high-throughput DNA sequencing are allowing faster and more affordable generation of molecular phylogenetic trees for many organisms. However, resolving relationships at species level is still challenging, particularly for taxonomically difficult groups. Until recently, the classification of Ochna had been based only on morphological data. Here, we present the first comprehensive phylogenomic study for the genus using targeted sequencing with a custom probe kit. We sampled c. 85% of species to evaluate the current infrageneric classification. Our results show that the data generated using the custom probe kit are effective in resolving relationships in the genus, revealing three sections consistent with the current classification and a new section consisting of species from Madagascar and the Mascarene Islands. Our results provide the first insights into the evolutionary relationships of several widespread and morphologically diverse species numerous poorly known and potentially new species to science. We demonstrate that for morphologically challenging groups such as Ochna , an integrated approach to classification is essential. Phylogenomic results are only informative when derived from accurately named samples. There is a symbiotic relationship between molecular phylogenomics and morphology-based taxonomy, with taxonomic expertise a requirement to accurately interpret the phylogenomic results. [ABSTRACT FROM AUTHOR]

Monocots account for a quarter of angiosperm species richness and are among the most economically and culturally important plants, including cereals (grasses), palms, orchids and lilies. Previous investigations of correlates of monocot species diversity have varied in scale and usually concentrated on a few drivers of diversification. Here, to disentangle the correlates of monocot diversity, we reconstructed a genus-level phylogenetic tree (1987 of the 2713 genera) and compiled an extensive database of abiotic, biotic and geographical characteristics to assess whether differences in these traits correlate with the vast asymmetrical species richness among genera present in this clade. Our results support several classical biodiversity theories, including species-area relationships, and latitudinal and elevational diversity gradients. Furthermore, interactions among these factors explain an additional 10% of the variation (compared to 36% from the main effects alone). We conclude that higher species richness among monocot genera is associated with geographical variables, especially larger ranges and lower elevations, rather than physical environment or physiology. [ABSTRACT FROM AUTHOR]

The exceptionally high plant diversity of the Greater Cape Floristic Region ( GCFR) comprises a combination of ancient lineages and young radiations. A previous phylogenetic study of Aizoaceae subfamily Ruschioideae dated the radiation of this clade of > 1500 species in the GCFR to 3.8-8.7 Mya, establishing it as a flagship example of a diversification event triggered by the onset of a summer-arid climate in the region. However, a more recent analysis found an older age for the Ruschioideae lineage (17 Mya), suggesting that the group may in fact have originated much before the aridification of the region 10-15 Mya. Here, we reassess the tempo of radiation of ice plants by using the most complete generic-level phylogenetic tree for Aizoaceae to date, a revised calibration age and a new dating method. Our estimates of the age of the clade are even younger than initially thought (stem age 1.13-6.49 Mya), supporting the hypothesis that the radiation post-dates the establishment of an arid environment in the GCFR and firmly placing the radiation among the fastest in angiosperms (diversification rate of 4.4 species per million years). We also statistically examine environmental and morphological correlates of richness in ice plants and find that diversity is strongly linked with precipitation, temperature, topographic complexity and the evolution of highly succulent leaves and wide-band tracheids. © 2013 The Authors. Botanical Journal of the Linnean Society published by John Wiley & Sons Ltd on behalf of The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174, 110-129. [ABSTRACT FROM AUTHOR]