A new species of the lichen genus Physcia (lichen-forming Ascomycota) from Texas

A new species of foliose lichen, Physcia solistella Essl. & Egan, is described from central Texas, where it may be endemic. The species is characterized by the presence of numerous erect blastidia, and resembles an over-sized version of P. millegrana Degel., a very common species in much eastern North America. Physcia solistella can be distinguished from the latter species by its larger thallus and lobes, larger ascospores, paraplectenchymatous lower cortex, and K+ yellow medulla.