Resolving Species Delimitations in the Eugenia involucrata Group (Eugenia sect. Phyllocalyx - Myrtaceae) with Morphometric Analysis

Abstract—

Eugenia (Myrtaceae) is the largest genus of Neotropical Myrtaceae comprising ca. 1,100 species. Eugenia sect. Phyllocalyx is a group that is morphologically characterized by the presence of leaf-like bracts and showy sepals. During the taxonomic review of the section, a complex of species closely related to E. involucrata, including Eugenia calycina, E. cavalcanteana, E. suffrutescens, E. stricta, E. neoformosa, E. incertissima, and E. chodatii, was identified.We carried out a morphometric analysis and taxonomic review of these species. Measures of 12 vegetative and floral characters were sampled from 77 herbarium specimens, encompassing the morphological variability and the geographic distribution of the species. A principal component analysis (PCA) was carried out to test the morphological discontinuity within the complex. Separate morphological groups were not revealed by the PCA and therefore we propose E. involucrata to be a single, highly variable species. A recircumscription and nomenclatural update of E. involucrata are presented, including seven lectotypifications and 17 synonyms, of which seven are new.