General:
Common Name: The Rag Lichen. Descriptive of the pale, often somewhat tattered lobes of the species.
Small to medium stratified foliose lichen, corticate above and below, lacking soredia and isidia, lobes loosely attached, elongate, averaging to 1.5–5 (–7) mm wide, thin. Upper surface pale yellowish grey, usually wrinkled. Lower surface mostly black, bearing sparse, short, simple rhizines. Medulla white. Photobiont green.
Apothecia usually located along margins, especially near lobe tips, disc brown; spores simple, ovoid to subspherical, colourless, 8 per ascus. Pycnidia black, conspicuous.
Over conifers.
Notes: Esslingeriana is a monotypic genus restricted to western North America at temperate latitudes. For points of distinction with similar species in other genera, see the descriptions under Platismatia.

Reactions:
Cortex K+ yellow, PD+ pale yellow; medulla K- or K+ pale violet.

Contents:
Atranorin, endocrocin, and two unknown substances.

Source:  Lichens of British Columbia

If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.

Illustration By:  Trevor Goward

Synonyms and Alternate Names:
Cetraria idahoensis Essl.