Untangling the taxonomy and geographic distribution of Quararibea floribunda (Malvaceae: Malvoideae)

Abstract

Quararibea floribunda, a species endemic to Brazil, is poorly studied taxonomically, and little is known about its ecology and conservation status. Since its publication in 1842, only a few studies have reported on its morphological circumscription, thus remaining as a complex in the taxonomy of Quararibea. In addition, little is known about its geographic distribution, which, according to most authors, is restricted to the Cerrado Biome, characterized mainly by its dry forests. Therefore, we herein review and clarify the morphological circumscription and distribution of Q. floribunda in different vegetation types, designate a lectotype, and recognize its conservation status as vulnerable (VU). The present study is based on analysis of protologues and further pertinent literature. Several herbaria were consulted, both in person and online. Fieldwork was done between 2017 and 2020 in different locations of midwestern and southeastern Brazil, mainly in dry forests of the Cerrado Biome. We confirm that Q. floribunda also occurs in the Atlantic Forest Biome and that it is not exclusive to the Cerrado Biome, as previously thought. All known populations in this biome inhabit humid habitats, and as such, they are closer to the vegetation of the Atlantic Forest Biome than the typical Cerrado dry forests. In addition to assessing the conservation status of Q. floribunda, we evaluate its nomenclatural history, leading to the designation of a lectotype, finally highlighting vegetative and floral diagnostic characters. A distribution map is provided, as well as a morphological comparative analysis between species with foliar domatia in extra-Amazonian Brazil.