Molecular systematics has clarified the limits of Loganiaceae (Gentianales), the tribal circumscriptions and the phylogenetic relationships within the family. Loganieae includes seven genera; however, generic boundaries remain untested and intergeneric relationships are largely unknown. The chloroplast intron petD and the nuclear ribosomal ETS were sequenced for 37 ingroup accessions, including all genera of Loganieae, to infer generic and infrageneric boundaries and intergeneric relationships within the tribe. Maximum parsimony and Bayesian analyses resolved several strongly supported clades. Mitreola s. str. was placed sister to the rest of Loganieae. The south-western Australian endemic, Mitreola minima B.J.Conn, was placed sister to Mitrasacme, Schizacme and Phyllangium, rendering Mitreola polyphyletic. Mitrasacme, Logania section Logania and L. section Stomandra were each strongly supported as monophyletic, but there was no support for the monophyly of Logania. Geniostoma was paraphyletic with respect to a monophyletic Labordia. It is here recommended that Mitreola minima be afforded generic status and that the three species of Labordia used in the present study be reduced to synonymy of Geniostoma. Additional sampling is needed to clarify the relationship between Logania section Logania and L. section Stomandra and to increase support for intergeneric relationships in Loganieae.
Hedyotis, Oldenlandia and related genera (Rubiaceae: Spermacoceae) comprise a morphologically recognisable group within Spermacoceae, characterised by the presence of raphides, more or less fimbriate stipules, 4‐merous flowers, bicarpellate gynoecia, multiovulate locules, peltate placentas and (generally) tricolporate pollen, but generic‐level taxonomy within the group has long been problematic. Recent molecular phylogenetic studies have made significant progress in our understanding of generic limits in the group internationally but have included little Australian material. This study includes broad geographic sampling and near complete representation of Australian taxa in maximum likelihood and Bayesian phylogenetic analyses of chloroplast (rps16, petD) and nuclear ribosomal (ITS, ETS) nucleotide sequence data to infer the phylogeny of the Spermacoceae and resolve the generic‐level classification of Australian taxa in the group. Two Australian species (Hedyotis novoguineensis, H. philippensis) were placed in Hedyotis. All remaining native Australian taxa currently accepted in Hedyotis, Oldenlandia and Synaptantha were placed within a large clade with an Asian‐Australian‐Pacific distribution. This clade includes Debia, Dimetia, Involucrella, Kadua, Exallage, Leptopetalum, Scleromitrion and Synaptantha, with Australian taxa included in clades corresponding to the latter four genera. The remaining native Australian species currently accepted in Oldenlandia are placed in two additional clades within the Asian‐Australian‐Pacific clade, and two new endemic Australian genera, Dolichocarpa and Paranotis, are here described to accommodate them. Oldenlandia s.str. is represented in Australia only by the introduced weed O. corymbosa. The morphology and geographic distribution of genera represented in Australia is discussed. New combinations in Scleromitrion and recommendations for accepted names in Exallage and Leptopetalum in Australia are provided, as is a key to the genera of the Spermacoceae (excluding the Spermacoce clade) in Australia.
Species of Mitrasacme occurring in Australia were revised for the Flora of Australia project in 1996, but the genus has never been revised as a whole. A checklist of the names of Mitrasacme species that occur outside Australia is presented here, together with their taxonomic status, known distribution and notes on their morphological affinities.
Paranotis halfordii K.L.Gibbons & S.J.Dillon, a new species from the Dampierland and Central Kimberley bioregions of Western Australia, is here described. Paranotis Pedley ex K.L.Gibbons was recently described to include some Australian species previously included in Oldenlandia L. A key to the species of Paranotis is provided.
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