Parmelia fraudans

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Parmelia fraudans is a leafy lichen in the Parmeliaceae family that grows on rocks in Europe and North America, from Alaska to Mexico. In Canada, it was newly recorded in Nova Scotia in 2022. Its global conservation status is Secure (NatureServe).

Taxonomy and history
- It was first named as a subspecies of Parmelia saxatilis by William Nylander in 1861 and was raised to species status in 1869.
- Molecular studies place it in the Parmelia sulcata group, with diversification beginning about 3.3 million years ago in the Pliocene.

What it looks like
- The thallus (the lichen body) is 4–16 cm across, tightly attached to rock.
- Lobes are 1–4 mm wide, grey to yellowish grey, smooth to slightly pitted, with many soredia along the margins.
- The medulla is white; the undersurface is black in the center and brown toward the edges; many black rhizines help it cling to rock.
- Apothecia (rare) are 2–4 mm in diameter with dark brown discs; soredia may appear at the margins.
- Spores are ellipsoid, 10–12 by 5–6 micrometers.

Chemistry and distinguishing features
- Cortex tests: K+ yellow; C−, KC−, P+ yellow.
- Medulla tests: K+ yellow to deep red; C−, KC−, P+ orange.
- Secondary compounds: atranorin and chloroatranorin in the cortex; usnic acid in the soralia; salazinic acid as a major medulla component (with minor consalazinic and protolichesterinic acids).
- The yellow color of the soridia from usnic acid is a distinctive feature in Parmelia.

Distribution notes
- Europe: Czech Republic, Estonia, France, Finland, Greenland, Norway, Russia, Sweden, Slovakia.
- North America: Alaska to Mexico; common on rocks.
- Canada: rare in the east; new record in Nova Scotia (2022).
- Conservation: In Estonia, the species was listed as critically endangered in 2019 due to shrinking range and population. Globally, it is considered Secure.