Rhynchospora waytii (Cyperaceae): A New Species with an Intriguing Disjunct Distribution in Brazil and Argentina

During the first author's doctoral research, in part developed at the New York Botanical Garden and guided by William Wayt Thomas, several new species of Rhynchospora were discovered when revising NY herbarium specimens. In this study, we describe and name one of these species as Rhynchospora waytii, in honor of this renowned sedge specialist and friend. Rhynchospora waytii is closely related to R. nanuzae but displays distinguishing characteristics such as broader leaves, inconspicuous rhizomes, and larger spikelets and stylopodia. It also exhibits a peculiar disjunct distribution, occurring in Brazil and Argentina, which is explored here with models of geographical range evolution and suitable area of occupancy. Our analysis suggests that suitable habitats have historically existed along the Atlantic coast, extending to the La Plata estuary, near the location where the Argentinian specimens were collected.