Nephroma helviticum is commonly known as Fringed Kidney Lichen as the 8cm diameter, loosely appressed foliose lichen slightly resembles a kidney. The upper surface of the thallus is of a darker brown than the lower surface. Fine hair covers the lower thallus surface. The lobes of the thallus are approximately 5mm wide. Reproduction occurs via isidia along the thallus margins and tooth-like lobules. N. helveticum has blue green algae as the primary photobiont. In addition to the asexual reproductive structures isidia and lobules, sexual apothecia are commonly observed on the underside of lobe tips.
Mossy rocks and woody plants of moist shady habitats are the typical substrate of N. helveticum. Often these criteria are met by riparian forests at low elevations. N. helveticum is more tolerant of dry and arid areas than other species of Nephroma.
N. helvetica is easy to distinguish from other species of Nephroma by the presence of both the marginal isidia and lobules. Western populations of N. helvetica have a thicker thallus than the eastern populations. The two populations are deemed different varities, var. sipeanum in the west and var. helvetica in the east.
Brodo, I.M., S.D. Sharnoff and S. Sharnoff (2001) Lichens of North America. Yale University Press, New Haven, Connecticut.
McCune, B. and L. Geiser (2009) Macrolichens of the Pacific Northwest. Oregon State University Press, Corvallis, Oregon.