The study of online digitized specimens revalidates Andersonglossum boreale as a species different from A. virginianum (Boraginaceae)

Abstract

Cynoglossum virginianum L., now transferred to the genus Andersonglossum as A. virginianum (L.) J.I.Cohen, has been traditionally considered to be formed by two infraspecific taxa: var. virginianum, and var. boreale (Fernald) Cooperr. The var. boreale was originally described as an independent species, Cynoglossum boreale Fernald, and remained treated as such until its combination as a variety of C. virginianum. However, no analysis exists that objectively compares both taxa in order to properly assess their taxonomic relationships. We performed a morphometric study to help elucidate their taxonomy. We found that both species are distinguishable using a few characters, despite slight overlap in nutlet length, corolla diameter, and calyx length, all traditionally considered to identify both taxa. The relatively large amount of variation in calyx dimensions seems to be the reason for most recent authors treating the two taxa at varietal rank. We provide the new combination Andersonglossum boreale (Fernald) Jim.Mejías, J.I.Cohen & Naczi to allow treating Cynoglossum boreale as a distinct species under its new generic circumscription.