Distribution patterns, Diversity, and Endemism of Melochia L. (Byttnerioideae - Malvaceae) in Brazil.

Melochia (Byttnerioideae - Malvaceae) is widely distributed across tropical and subtropical regions. In Brazil, however, its distribution, species richness, diversity, and endemism remain poorly understood. The present study aimed to analyze the biogeography of Melochia and infer which distribution patterns best reflect its geographic distribution in Brazil and where its centers of diversity and endemism are located. Species occurrence data were compiled from online databases, resulting in 4,136 cleaned records representing 27 species. Richness and diversity analyses were conducted using DIVA-GIS, while QGIS was used to create the distribution maps. Parsimony Analysis of Endemicity was performed with PAUP. Our results indicate that most Melochia species are widely distributed. Seven areas of diversity were identified: Pantanal, Central Brazilian Cerrado, Northern and Southern Espinhaço Range, Serra dos Carajás, Tapajós, and Raposa Serra do Sol Indigenous Land. Two areas of endemism were detected: Chapada Diamantina, and Chapada do Araripe. These patterns highlight the ecological relevance of Melochia across varied environmental gradients and its biogeographical structure, particularly in the Central-West and Espinhaço Range. The study also reveals significant knowledge gaps and underrepresentation of certain species in herbarium collections and databases, stressing the need for increased botanical exploration and habitat protection.