Systematics and Evolution of Rhynchospora section Pauciflorae Kük. (Cyperaceae)

taxonomy, filogeny, morfology, Rhynchosporae.

Rhynchospora Vahl (Cyperaceae) is a genus with high diversity in the Americas, especially in the Neotropics, with about 400 species and significant levels of endemism in tropical and subtropical savannas. It is also the richest genus of Cyperaceae in Brazil, occurring in all states and phytogeographic domains. The genus was revised in 1949 and compartmentalized by Kükenthal into two subgenera and 28 sections, which have been revised by other investigators. Rhynchospora sect. Pauciflorae has never been revised since its creation by Kükenthal in 1949, is part of an informal group created by the author, “Pars Capitatae”, together with the sister group, R. sect. Pluriflorae. Authors reviewing R. sect. Pluriflorae highlight the importance of taxonomic and systematic studies in R. sect. Pauciflorae, in order to test the monophyly of the section, and better understand its relationship with the sister group, since the sections share characters that were considered synapomorphic by Kükenthal. Rhynchospora sect. Pauciflorae currently has 23 valid species, where 12 occur in the Americas (subsection Plumoso-setosae), and the others are restricted to Asia and Australia. The objective of this project is to carry out taxonomic, morphological and phylogenetic studies on Rhynchospora sect. Pauciflorae (Cyperaceae),

seeking to elucidate the biodiversity, understand the evolutionary relationships and circumscriptions of the studied taxa. Field expeditions are being carried out to collect botanical material, as well as consultation in person with Brazilian herbaria collections, databases and images of specimens from international herbaria. The taxonomic treatment is being carried out by consulting the original works and nomenclatural types. Images are being made in SEM of the external micromorphology of the fruits, and determinations of their composition through EDS (Dispersive Energy Detector). The sequencing of the plastid regions trnT-trnL, trnL-trnF, the intron trnL, and the ribosomal regions ETS and ITS will be carried out. Phylogenies will be estimated by Maximum Likelihood (ML) and Bayesian Inference (IB). The reconstruction of the ancestral characters will be done using Mesquite 3.04, with parsimonious reconstruction methods. A manuscript describing a new species of R. sect. Pluriflorae is presented., and manuscript containing lectotypifications in R. sect. Pauciflorae. Also is provided a complete description, and 13 other in-progress descriptions of R.sect. Pauciflorae. Rhynchospora denticulata Huber, is being recognized again as an accepted species.