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Digitaria is a large pantropical genus, which includes a number of economically problematic agricultural weeds. Difficulties in species identification and the circumscription of the genus have previously hindered progress in understanding its evolution and developing a stable classification. We investigate the evolutionary history of Digitaria by combining two approaches: (i) phylogenetic analyses of the currently available Sanger sequence data with previously unpublished sequences mainly from South East Asia, and (ii) newly generated genomic data from low-copy nuclear genes obtained using the Angiosperms353 probe kit, with new data mainly from Madagascar. Both methods gave congruent results. The combination of these results allowed us to confirm a new clade structure within Digitaria lineages, in partial agreement with the previous morphology-based classifications. We confirm that Digitaria as traditionally circumscribed is not monophyletic, comprising Anthephora , Baptorhachis , Chaetopoa , and Chlorocalymma. We present an inference of key character evolution with morphological support for clades with spikelets arranged in binate and ternate groups, with variable trichome morphology, spikelet length, and culm length. Geographical clade structure is also observed. No phylogenetic signal of weedy function was observed. [ABSTRACT FROM AUTHOR]

With 14 species, Badula (Primulaceae) is the most species-rich endemic angiosperm genus of the Mascarene Archipelago. The relationship between Badula and its ally Oncostemum ( c. 100 spp; Madagascar and the Comoros Islands) is uncertain, with implications for the circumscription of Badula as a Mascarene endemic. Within Badula, species rarity (several being critically endangered) and a paucity of herbarium specimens hamper proper species delimitations. Here, we estimate the phylogenetic relationships of Badula based on DNA sequence data from the nuclear ribosomal internal transcribed spacer (ITS) and plastid trnS-trnG-trnG regions with complete taxon sampling of the genus and three samples or more of each taxon. The results strongly supported the monophyly of Badula. Paraphyly of Oncostemum was inferred with weak support; explicit hypothesis testing did not favour this hypothesis over one that forced the monophyly of Oncostemum. Monophyly of several Badula spp. was supported, particularly for taxa from the older islands of Mauritius and Rodrigues. Badula is inferred to have reached the Mascarene Archipelago through a single colonization event. The majority of species segregated into island clades, implying that few, rather than multiple, colonization events have occurred in Badula among the islands of the archipelago. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 169, 284-296. [ABSTRACT FROM AUTHOR]