The current knowledge about the distribution of Portulaca species (Portulacaceae) within the Balkan Peninsula

Abstract

This study addresses the complex taxonomy and distribution of the genus Portulaca L. (Portulacaceae) within the Balkans, focusing on the often-debated species composition and distribution patterns in the P. oleracea aggregate. Our research aims to resolve this ambiguity by addressing two key questions: 1) Which Portulaca taxa are present in the Balkans, and 2) What is the current distribution of these taxa here? To achieve this, we conducted literature reviews, seed collection, species identification using micromorphological characteristics, and distribution analysis. Our findings reveal the presence of four distinct species in the Balkans: P. oleracea agg., P. grandiflora, P. pilosa and P. umbraticola. Additionally, within the P. oleracea complex, twelve microspecies have been identified, primarily differentiated based on seed micromorphology. Besides, five species (P. daninii, P. granulato-stellulata, P. rausii, P. sardoa, and P. trituberculata) have been documented in Montenegro, and one species (P. nitida) – in Slovenia for the first time. This study provides a valuable contribution to the botanical knowledge of the Balkan Peninsula, offering the recommendations for future studies of the P. oleracea complex for the solution of the taxonomic puzzle in this aggregate.