Gowardia zebrina sp. nov., a new species in a little-known genus of arctic-alpine lichens (Parmeliaceae)

The fruticose lichen genus Gowardia (Parmeliaceae) was recently segregated from Alectoria based on phylogeny, morphology, secondary chemistry, ecology and distribution. As currently circumscribed, Gowardia comprises two wide-ranging species of arctic-alpine regions. Here we describe a third species, G. zebrina sp. nov., apparently endemic to subalpine regions in mountainous northwestern North America. Gowardia zebrina differs from other species in the genus by its combined subpendent habit, uniformly capillary branches, predominantly isotomic branching, pale-and-dark banding of the terminal branches, and epiphytic ecology. Morphological examination of North American herbarium specimens filed under A. nigricans suggests the existence of several additional undescribed species of Gowardia. A brief overview of morphological diversity in these species is given, shedding new light on the question of whether Gowardia should be subsumed under Alectoria, as some have suggested, or is more appropriately recognized as a distinct genus.