Rhynchospora Vahl (Cyperaceae) is a genus with high diversity in the Americas, especially in the Neotropics, with about 400 known species and significant levels of endemism in tropical and subtropical savannas. It is also the Cyperaceae genus with the highest species richness in Brazil, occurring in all states and phytogeographic domains. The genus was revised in 1949 and divided by Kükenthal into two subgenera and 28 sections, which have been revised by other researchers since then. Rhynchospora sect. Pauciflorae has never been revised since its creation by Kükenthal in 1949. It is part of an informal group created by the author, “Pars Capitatae,” which also includes the sister group, R. sect. Pluriflorae. Authors who revised R. sect. Pluriflorae highlighted the importance of taxonomic and systematic studies on R. sect. Pauciflorae to test the monophyly of the section and better understand its relationship with the sister section, as the sections share characteristics that were considered synapomorphic by Kükenthal. Rhynchospora sect. Pauciflorae currently includes 23 valid species, 12 of which occur in the Americas (subsection Plumoso-setosae), while 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) to clarify biodiversity, understand evolutionary relationships, and define the circumscription of the studied taxa. Field expeditions were carried out for botanical material collection, as well as in-person consultations with Brazilian and U.S. herbarium collections, and databases and images of specimens from international herbariums. Taxonomic treatment was conducted through consultation of original works and nomenclatural types. Scanning electron microscope (SEM) images of the external micromorphology of the fruits were made, and their composition was determined using Energy Dispersive X-ray Spectroscopy (EDS). Sequencing of the plastidial region trnL-trnF, the intron trnL, and the ribosomal regions ETS and ITS was performed. Phylogenies were estimated using Maximum Likelihood (ML) and Bayesian Inference (BI). A published article describing a new species of R. sect. Pluriflorae, an article containing lectotypifications in R. sect. Pauciflorae, a published article, and a manuscript describing new species for sect. Pauciflorae are presented. Additionally, Rhynchospora unisetosa is proposed as a new synonym for R. hirta, and Rhynchospora denticulata Huber is being recognized again as an accepted species.