A Taxonomic Revision of the Lathberry Clade of Eugenia (Myrtaceae)

Abstract— The Lathberry Clade includes seven species of Eugenia sect. Umbellatae (Myrtaceae) distributed from Puerto Rico through the Lesser Antilles. Members of the Lathberry Clade are trees and shrubs distinguished from other Antillean species by a combination of dull twigs, glabrous leaves with a raised midvein, glomerate or fasciculate inflorescences predominantly borne below the leaves on old wood, closely spaced and ascending inflorescence bracts, spheroidal fruits turning red or purple at maturity with the calyx lobes erect or spreading and often torn away, and a unique, large deletion in the plastid psbA-trnH intergenic spacer region. We examined the morphology, leaf venation, and seed coat anatomy of the Lathberry Clade and constructed a phylogeny using non-coding nuclear genetic regions. The taxonomic treatment includes a key to the species, distribution maps, and extinction risk assessments. We recognize Eugenia sintenisii from Puerto Rico and E. cordata var. caribaea (nom. nov.) from the Lesser Antilles in place of E. cordata var. sintenisii and synonymize E. earhartii with E. stirpiflora. Six lectotypes are designated.