Molecular and morphological data resurrect the long neglected Carex laxula (Cyperaceae) and expand its range in the western Mediterranean

Abstract

Carex sylvatica subsp. paui is a poorly studied taxon considered endemic from a few places in the western Mediterranean. It has been frequently misidentified as C. sylvatica subsp. sylvatica. To date, it has been reported only from the NE Iberian Peninsula and the NW Africa. We use molecular -nuclear ribosomal and plastid sequences- and morphological data to shed light on the taxonomic circumscription and distribution of this taxon, especially regarding its distinction from the type subspecies. The genetic data support the recognition of C. sylvatica subsp. paui as an independent taxon, and confirm new records from the Balearic and Tuscan archipelagos. It implies a considerable increase in its range and a new taxon for the Italian flora. Strikingly, the morphometric analyses revealed that the Sicilian type specimen of C.laxula identifies this species with C. sylvatica subsp. paui. We consider that the taxon should be ranked at the species level. Based on thepriority of the name C. laxula over C. paui, we subsume C. sylvaticasubsp. paui in C. laxula. We also provide notes on the ecology of thespecies.