Parmelia
Parmelia Ach., 1803
| Common name | Shield Lichens |
|---|---|
| Field Characters | Medium-sized, leafy chlorolichens. Lobes narrow, often attached to their substrate throughout. Upper surface blue-grey to brown-grey, typically with a “hammered” or reticulate appearance due to a series of depressions. Pseudocyphellae common, typically elongate, along ridges and margins, often developing into soralia. Lower surface black with abundant rhizines. Isidia or soredia common, apothecia rare. Most species have angular lobes (think maple leaves), but a few have more rounded lobes. |
| Similar species & genera |
Hypogymnia: with experience these two genera are easily discriminated – Hypogymnia has inflated, tubular lobes and no rhizines. Because they both have some super common species that often grow intertwined they are easily confused by beginners. |
| Ecology | Most species in Alberta are epiphytic or on downed wood, a few are saxicolous. Parmelia are most common in forested sites, but some species are found occasionally in the grasslands. |
| Chemistry | Upper cortex PD+ pale yellow or PD-, K+ yellow, C-, KC- or rarely KC+ yellow, UV- (atranorin, chloroatranorin, rarely usnic acid). Medulla has some combination of orcinol depsides or depsidones, ß-orcinol depsides or depsidones or aliphatic acids. |
| Molecular support |
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| Links |
Species recorded in Alberta: 5… now 6! We recently confirmed the presence of another species in Alberta, but it hasn’t been formally reported or published yet: P. barrenoae, welcome to Alberta.
- P. barrenoae Divakar, M.C. Molina & A. Crespo, 2005 (DH)
- P. fraudans (Nyl.) Nyl.
- P. hygrophila Goward & Ahti
- P. omphalodes (L.) Ach. subsp. omphalodes (ACIMS, ABMI)
- P. saxatilis (L.) Ach. (ACIMS)
- P. sulcata Taylor (ACIMS, ABMI)
DICHOTOMOUS KEY
1a. Isidiate; rhizines simple to forked…..2
1b. Isidia lacking…..4
2a. Isidia mostly laminal, short, granular to globular to sparingly branched, occasionally soredia-like, dull or weakly shiny; typically corticolous, rarely saxicolous…..P. hygrophila
2b. Isidia mostly marginal, usually saxicolous…..3
3a. Isidia long-cylindrical, flattened or occasionally richly branched, shiny…..P. saxatilis
3b. Isidia dull or weakly shiny, short, granular to globular; soralia yellowish (usnic acid)…..P. fraudans
4a. Soredia lacking; upper surface grayish to brownish, often very dark in exposed habitats; typically alpine or subalpine, on sod, rock or mosses over rock; laminal pseudocyphellae sparse to abundant (reticulate whitish marks, especially towards margins…..P. omphalodes subsp. omphalodes
4b. Sorediate…..5
5a. Soredia powdery, soralia becoming excavate; corticolous…..6
5b. Soredia coarsely granular to isidiate; rhizines simple or dichotomously forked; corticolous or saxicolous…..7
6a. Soralia only partially excavate at maturity, not completely eroded, rhizines squarrose at maturity; one of Alberta’s most common, abundant lichens….P. sulcata
6b. Soralia becoming deeply excavate and eroded, rhizines simple or at most branched at maturity; apparently rare, restricted to the SW corner of the province…..P. barrenoae
7a. Soredia/isidia mainly laminal; generally corticolous…..P. hygrophila
7b. Soredia/isidia mostly marginal; saxicolous; soredia yellowish due to usnic acid in soralia…..P. fraudans
RENR Students: Know Parmelia sulcata– be able to key this species out or recognize it (it is also covered in Brodo et al. 2001 and Goward 1999).
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.
