Arctoparmelia
Arctoparmelia Hale, 1986
| Common name | Ring Lichens |
|---|---|
| Field Characters | Leafy, yellow chlorolichen. Thalli appressed, forming concentric rings, lobes narrow, to 0.5 cm across. Upper cortex pale yellow, dull, may be pruinose, lacking pseudocyphellae. Typically either apotheciate or sorediate. Lower cortex white to pale brown or mousy-grey to purplish black, with sparse simple rhizines. Apothecia common in some species, relatively large, on short stipes, with brown disc and thin yellow thalline margins (lecanorine). Pycnidia common, laminal or marginal. |
| Similar species & genera |
Parmeliopsis ambigua: rare on rocks, but when it does occur in that microhabitat it can sometimes be differentiated by a brown lower cortex. However, you may require thin layer chromatography to be certain. Arctoparmelia contains alectoronic acid in the medulla while P. ambigua contains divaricatic acid: both react UV+ blue white.Xanthoparmelia: rhizines commonly branched, lower cortex often black or dark brown (vs. white or mouse grey), cortices often shiny, lacking pruina, medulla often PD+ orange to red. |
| Ecology | Saxicolous, typically on granitic rock, very rarely on downed wood. Largely restricted to the shield and mountain regions of Alberta, with sparse occurrences in the boreal and foothills. |
| Chemistry | Upper cortex KC+ yellow, K+ yellow, C-, PD- or PD+ pale yellow, UV- (usnic acid, atranorin). Medulla KC+red, K-, C-, PD-, UV+ white (alectoronic acid, ±aliphatic acids). |
| Molecular support |
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| Links |
Species recorded in Alberta: 4
- A. centrifuga (L.) Hale Syns.: Parmelia centrifuga, P. aleuritica, Parmelia halseyana, Xanthoparmelia centrifuga (ACIMS)
- A. incurva (Pers.) Hale Syns.: Parmelia incurva, Xanthoparmelia incurva (ACIMS)
- A. separata (Th. Fr.) Hale Syns.: Parmelia separata, P. birulae var. grumosa, Xanthoparmelia separata (ACIMS)
- A. subcentrifuga (Oxner) Hale Syns.: Parmelia subcentrifuga, Xanthoparmelia subcentrifuga (ACIMS)
DICHOTOMOUS KEY
1a. On soil, rocks, or vagrant in mountains, prairies and badlands; medulla UV-, cortex often PD+ orange to red; rhizines commonly branched; cortices often shiny….See Xanthoparmelia key
1b. On rock (mainly silicious) in artic and boreal regions; medulla UV+ blue white (alectoronic acid), cortex PD-; rhizines simple; cortices dull…..2
2a. Soredia present; arctic/alpine distribution…..3
2b. Soredia absent; arctic/boreal distribution…..4
3a. Soredia diffuse on the upper surface; lower surface mouse-gray; lobes flat…..A. subcentrifuga
3b. Soredia in discrete round to irregular soralia; lower cortex gray to dark; lobes convex, narrow, crowded (brain-like)…..A. incurva
4a. Lower surface grey to black or purplish black, especially towards the centre of the thallus…..A. separata
4b. Lower surface pale…..A. centrifuga
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.
McMullin, R. T. 2023. Lichens. The macrolichens of Ontario and the Great Lakes Region of the United States. Firefly Books, Richmond Hill, Ontario.
Apothecium (plural: apothecia) Disc or cup-shaped structures formed by the fungal symbiont, where sexual spores are created. The spore-containing surface is usually a different colour than the thallus of the lichen. Line drawing reproduced courtesy of BC Ministry of Forests and T. Goward, from Goward et al. 1994, fig. 9a.
