Revisiting the taxonomy of Dioclea and related genera (Leguminosae, Papilionoideae), with new generic circumscriptions.

The Dioclea clade comprises four genera and aproximately 60 species of the tribe Diocleae: Cleobulia (4 species), Cymbosema (1), Dioclea (ca. 50), Luzonia (1) and Macropsychanthus (3-4). Dioclea has been demonstrated to be a non-monophyletic genus, but low sampling in previous phylogenetic studies hampered the adoption of new taxonomic arrangements. We carried out densely sampled phylogenetic analyses of the Dioclea clade using molecular markers that had performed well in previous studies: the ITS and ETS nuclear ribosomal regions and the plastid trnK/matK. Our results support the maintenance of the genera Cleobulia and Cymbosema with their current circumscriptions, but confirmed the polyphyly of Dioclea, with its species falling into three different positions: (1) the puzzling species, Dioclea paniculata, was highly supported as a member of the Galactia clade; (2) Dioclea subg. Dioclea appeared as sister to a clade composed of Cleobulia and Cymbosema; and (3) the species of Dioclea subgenera Pachylobium and Platylobium composed a paraphyletic grade nesting the genera Luzonia and Macropsychanthus. We thus propose that the circumscription of Dioclea should be restricted to Dioclea subg. Dioclea, with 13 species and that the limits of Macropsychanthus should be widened to include the genus Luzonia, as well as the Dioclea subgenera Pachylobium and Platylobium, with 46 species. Taxonomic summaries, new combinations and synonyms are presented for all genera of the Dioclea clade. Cleobulia and Cymbosema were retained in their original circumscriptions. We presented an illustrated taxonomic conspectus of all genera of the Dioclea clade including 44 new combinations, one new name, ten new synonyms, two re-established holotypes, 38 lectotypes, two epitypes and one neotype.

A dated phylogeny of the papilionoid legume genus Canavalia reveals recent diversification by a pantropical liana lineage.

Canavalia is a pantropical legume genus of lianas comprising approximately 60 species distributed in a wide range of habitats. In the last taxonomic revision, the genus was divided into four subgenera: Canavalia (Pantropical), Catodonia (Neotropical, excepting one species also found in the Old World), Maunaloa (Hawaiian), and Wenderothia (Neotropical). In this study, we reconstructed the phylogeny of Canavalia using a broad taxon sampling and analyses of nuclear (ETS and ITS) and plastid markers (trnK/matK). We evaluated the infrageneric classification of the genus and investigated its biogeographical history using molecular dating analyses and ancestral area reconstructions. The phylogenetic analyses resolved subgenus Wenderothia as monophyletic. Subgenus Catodonia needs to be recircumscribed and the relationships between subgenera Canavalia and Maunaloa remain unclear. Canavalia arose during the Miocene with a mean stem age estimate of 13.8Ma and mean crown age estimate of 8.7Ma, and most extant species evolved during the Pleistocene. Several climatic and geological events are chronologically coincident with the divergence of the major clades of Canavalia (glacial/interglacial periods, Andes uplift and the formation of Pebas and post-Pebas systems, closure of the Isthmus of Panama, and change in the direction of ocean currents). Ancestral area reconstructions for the early divergence of the genus are equivocal, although, some evidence suggests Canavalia originated in the wet forests of South America and achieved its current pantropical distribution through recent transoceanic dispersal. The evolution of Canavalia is better explained by a series of several processes than by discrete historical events.

Phylogenetic relationships of Echinolaena and Ichnanthus within Panicoideae (Poaceae) reveal two new genera of tropical grasses.

Echinolaena and Ichnanthus are two tropical grass genera distributed mostly in the Americas, characterized by the presence of rachilla appendages in the shape of convex swellings, scars or wings at the base of the upper anthecium. However, recent studies have shown that rachilla appendages arose several times independently in several groups within Paniceae and Paspaleae (Panicoideae). Thus, this study aimed to assess the monophyly of Echinolaena and Ichnanthus and their relationship to other genera of Paniceae and Paspaleae, especially those including species with rachilla appendages. Parsimony and Bayesian analyses of the cpDNA regions ndhF, rpl16, trnH-(rps19)-psbA, trnL-trnF, trnS-(psbZ)-trnG, and the rDNA ITS region included 29 of the 39 known species of Echinolaena and Ichnanthus, 23 of which were sampled for the first time. The multiple loci analyses indicated that Echinolaena and Ichnanthus are polyphyletic in their current circumscriptions, with species in four distinct lineages within subtribe Paspalinae, each one characterized by a single type of rachilla appendage. Thus, Echinolaena and Ichnanthus are each circumscribed in a narrow sense, and the other two lineages excluded from them are proposed as the new genera Hildaea and Oedochloa, resulting in 15 new combinations and the restablishment of I. oplismenoides Munro ex Döll.

A multilocus phylogenetic analysis reveals the monophyly of a recircumscribed papilionoid legume tribe Diocleae with well-supported generic relationships.

Deciphering the phylogenetic relationships within the species-rich Millettioid clade has persisted as one of the major challenges in the systematics and evolutionary history of papilionoid legumes (Leguminosae, Papilionoideae). Historically, the predominantly neotropical lianas of subtribe Diocleinae in the Millettioid legumes have been taxonomically tangled together with the largely heterogeneous tribe Phaseoleae. This work presents a comprehensive molecular phylogenetic analysis based on nuclear and chloroplast markers and includes all genera ever referred to Diocleae except for the monospecific Philippine Luzonia, resolving several key generic relationships within the Millettioid legumes. The first of two separate analyses includes 310 matK accessions and strongly supports the reestablishment of tribe Diocleae as a branch of the Millettioid clade. This work sheds greater light on the higher-level phylogeny of Diocleae and allows the recognition of three major lineages: the Canavalia, Dioclea, and Galactia clades. The second set of phylogenetic analyses utilized nuclear (ITS/5.8S and ETS) and plastid (matK and trnT-Y) DNA sequences to reveal (i) the monophyly of Canavalia and Cleobulia; (ii) the monophyly of Bionia with the exclusion of Bionia bella; (iii) the paraphyly of Dioclea with respect to Cleobulia, Cymbosema, and Macropsychanthus; (iv) the paraphyly of Cratylia with respect to the broadly polyphyletic Camptosema; and (v) the polyphyly of Galactia with species scattered widely across the tree.