First step towards a molecular phylogeny of Citharexylum (Verbenaceae).

MORONI, PABLO; O'LEARY, NATALY; FROST, LAURA

Ohio

Conferencia; Botany2020; 2020

Botanical Society of America

Citharexylum is a neotropical and subtropical genus with about 100 species of trees and shrubs where taxonomy and phylogeny remain unresolved. A molecular phylogenetic approach is taken to resolve infrageneric relationships in Citharexylum. Seven chloroplast regions, two nuclear ribosomal spacers, and six low-copy nuclear loci were analyzed for 176 accessions of 64 Citharexylum species. Phylogenetic analyses were conducted using maximum likelihood, Bayesian inference, and Bayesian multi-species coalescent approaches. Two major clades are found within Citharexylum, mostly, though not exclusively, defined by the geographical distribution, and referred as the Central American clade and the South American clade. The South American clade comprises most of the South American diversity and is further divided into two subclades, Sylvaticum and Andinum. The Central American clade comprises three subclades, recognized as Citharexylum, Mexicanum, and Affine, these last two are exclusively made up of Mexican taxa. A sixth clade is reconstructed as sister to the rest of the genus; it includes a single Mexican species, Citharexylum altamiranum. The six clades here recognized are best defined by geography, fruit color/maturation, flower color, and inflorescence architecture. Further studies in taxonomy are necessary in order to clarify the systematics of Citharexylym.