Is Genista anxantica (Fabaceae, Genisteae) worth of taxonomic recognition? An integrative approach

Genista anxantica is an extremophile taxon described by Michele Tenore and strictly endemic to the mephitic fields in Ansanto Valley (Mefite, Rocca San Felice, province of Avellino, Campania region, SW Italy). Its taxonomic distinctness from the widespread G. tinctoria subsp. tinctoria, initially undoubted, has later been long debated. Recent population genetic evidence suggests that the Mefite population represents an ecotype within G. tinctoria, shaped by extreme ecological conditions. In this contribution, we integrate morphological data and ploidy estimation by flow cytometry with ecological and genetic information to reassess its taxonomical status. Our results highlight the distinctness of G. anxantica as a local, genetically established variant adapted to a peculiar ecology. Accordingly, we propose the subspecific rank. The name G. anxantica is typified on a specimen preserved in Tenore’s herbarium (NAP, Botanical Garden of Naples).