Nephroma
Nephroma Ach., 1809
| Common name | Paw Lichens, Kidney Lichens |
|---|---|
| Field Characters | Variable, medium to large, leafy, bipartite cyanolichens or tripartite cephalolichens. Thalli appressed to ruffled, forming loonie-sized to hand-sized colonies. Upper cortex brown, grey or pale yellow, varying from smooth and shiny to dull and rough or even foveolate or reticulate. Vegetative propagules may be absent; when present, they vary from soredia, to isidia to lobules. Lower surface corticate, smooth or short-tomentose, one species with papillae, but always lacking rhizines. The tripartite species develop internal cephalodia that are quite cryptic, often visible as greyish bumps beneath the cortex when hydrated. Apothecia common, on the lower surface of reflexed lobe tips, with a brown, kidney-shaped disc, vaguely resembling the paw pads of a dog. |
| Similar genera |
Peltigera: apothecia held erect on the upper side of lobes, lower surface lacking a cortex and mostly with veins, interstices and well-developed rhizines.
Asahinae, Melanelia, Platismatia: chlorolichens with trebouxioid algae. |
| Ecology | Epiphytic or on downed wood (largely coniferous), some species terricolous or occasionally saxicolous. In Alberta this genus is occasional in the boreal, foothills and mountain regions, often in old, undisturbed forests, and absent from the parkland and grasslands. |
| Chemistry | In most species all spot tests negative, with zeorin and other triterpenes detectable by TLC. Nephroma arcticum is an exception, with upper cortex KC+ yellow, K- or K+ pale yellow, C-, PD-, UV- (usnic acid), medulla KC-, K- or K+ pale yellow, C- or C+ pale yellow, PD+ deep yellow, UV- (zeorin, nephroarctin, phenarctin). |
| Molecular support |
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| Links |
Species recorded or with potential to occur in Alberta: 8
- N. arcticum (L.) Torss. (ACIMS)
- N. bellum (Sprengel) Tuck. (ACIMS)
- N. expallidum (Nyl.) Nyl. (ACIMS)
- N. helveticum Ach. subsp. helveticum (ACIMS; rare)
- N. isidiosum (Nyl.) Gyelnik (ACIMS; rare)
- N. occultum Wetmore (McBride, BC; NA, UBC; not known for AB at present)
- N. parile (Ach.) Ach. (ACIMS)
- N. resupinatum (L.) Ach. (ACIMS)
Click here for a pdf key to the Nephroma of Alberta v2025
RENR Students: Know the species Nephroma arcticum, N. bellum & N. resupinatum – be able to key them out or recognize them (also covered in Brodo et al. 2001 and Goward et al. 1994).
Resources
Brodo, I. M. 2016. Keys to the lichens of North America. Revised and Expanded. Yale University Press, in collaboration with the Canadian Museum of Nature.
Brodo, I. M., S. D. Sharnoff, and S. Sharnoff. 2001. Lichens of North America. Yale University Press, New Haven and London.
Goward, T., B. McCune, and D. Meidinger. 1994. The Lichens of British Columbia Illustrated Keys. Part 1 – Foliose and Squamulose Species. Ministry of Forests Research Program, Province of British Columbia.
