Gracilaria vermiculophylla (Rhodophyta, Gracilariales) in Hog Island Bay, Virginia:: A cryptic alien and invasive macroalga and taxonomic correction

Gracilaria in Virginia, USA, is abundant and composed of thalli either having relatively flat or cylindrical branches. These two morphologies were referred to previously as G. foliifera (Forsskal) Bogesen and G. verrucosa (Hudson) Papenfuss. However, G. verrucosa is regarded an invalid name, and the flat specimens are now referred to as G. tikvahiae McLachlan. This has created confusion about the nomenclature of Gracilaria from this region. Here we document that the cylindrical form that dominates Hog Island Bay, Virginia, is G. vermiculophylla (Ohmi) Papenfuss, an alien macroalga from the West Pacific. Most of the ecological studies performed at the Long Term Ecological Research (LTER) site in Hog Island Bay used this cylindrical species. The present study clarifies the taxonomical status of this species, and we identify attributes that make this alien successful in turbid coastal lagoons.