Bonamia eustachioi (Convolvulaceae), a new species from the Brazilian Cerrado and Caatinga ANDRÉ LUIZ DA COSTA MOREIRA 1 ,ROBERTA KEYLA KOJIMA 2 , ROSANGELA SIMÃO-BIANCHINI 2 , AND T ACIANA BARBOSA CAVALCANTI 3 1 Campus Darcy Ribeiro Department of Botany, University of Brasília, Graduate Program in Botany, Brasília, DF 7091-900, Brazil; e-mail: moreirabiologo@yahoo.com.br 2 Research Group of Herbarium SP, Institute of Botany, 68041, São Paulo, SP 04301-902, Brazil; e-mail: keylakoji@gmail.com 3 Embrapa Genetic Resources and Biotechnology, Parque Estação Ecológica, 02372, Brasília, DF 70770- 900, Brazil; e-mail: taciana.cavalcanti@embrapa.br Abstract: Bonamia eustachioi is here described as a new species of Convolvulaceae from the states of Bahia and Minas Gerais, Brazil, where it grows in Caatinga and Cerrado vegetation. It is described, illustrated, and compared to similar species. Keywords: Brazilian savanna, conservation, Solanales, taxonomy. Brittonia, 73(2):203–210 (2021) DOI 10 1007/s12228-021-09662-z , . © 2021, by The New York Botanical Garden Press, Bronx, NY 10458-5126 U.S.A. Published Online: 22 March 2021 Bonamia Thouars (Convolvulaceae) is a mainly herbaceous genus, rarely climbing vines or sub- shrubs (Myint & Ward, 1968), characterized by free or partially free styles (Fig. 1), non-accrescent sepals, dehiscent fruits, and ovate, obovate, or ovate-cordate cotyledons (Austin & Staples, 1985; Breteler, 1992). The genus has a broad distribution in North and South America, East and West Africa, Madagascar, North and South Asia, and North and Central Australia (Lewis, 1971; Wood, 2013). Tax- onomic studies of Bonamia have resulted in differ- ent circumscriptions of its taxa (Choisy, 1845; Hallier, 1893, 1897; Myint & Ward, 1968; Austin & Staples, 1985). In the first synopsis of the genus, Hallier (1897) recognized only 28 species of Bonamia, while Myint & Ward (1968) recognized 45 species, 23 of which are neotropical. In the last ten years, sixteen new species have been described for the genus (Wood, 2013; Johnson, 2014; Moreira, et al., 2017, 2018, 2019a, b), and we estimate that Bonamia comprises about 65 species (Staples, 2019). Most of its taxa are represented by only one to five specimens in herbaria. Only a few species with large geographical distributions — e.g., B. agrostopolis (Vell.) Hallier f. and B. ferruginea (Choisy) Hallier f. — have a greater number of specimens. The total number specimens of all taxa of Bonamia is approximately 1400. The euripalynous condition of the genus has been a subject of discussion in the literature, and several studies have suggested that certain taxa of Bonamia with particularly divergent pollen mor- phologies might be better placed elsewhere, but without further specification (Hallier, 1897; Myint & Ward, 1968; Austin & Staples, 1985). Indeed, the genus was recovered as polyphyletic by Stefanovic et al. (2002) within the Tribe Cresseae, and ongoing phylogenetic studies (Moreira et al., unpubl. data) with more expansive sampling of species also support its non-mono- phyly. A taxonomic solution to the non- monophyly of Bonamia will likely require the erection of new genera to accommodate most of the Brazilian species, as well as the Australian and African species. Pollen morphology has figured prominently in the sectional classification of Bonamia. Pollen grains in the genus are euripalynous, monads, either polar and 3-colpate or apolar and pantocolpate (12–32 colpi) (Hallier, 1897; Moreira et al., 2019b). Within the genus, species display five distinct pollen types defined by