Myochroidea
Crustose lichens having a trebouxioid alga; thallus areolate, verruculose, subsquamulose, sorediate, or goniocystose-granular, of drab brown, olive or grey-green colours; apothecia matte or slightly glossy, orangish brown, brown or reddish brown, with a thin, slowly or rapidly receding rim formed of weakly gelatinized, densely branched and anastomosing hyphae; hypothecium colourless; hymenium formed of weakly to moderately branching and anastomosing paraphyses, often brown-pigmented in the walls at the tip; asci with a well-thickened tholus, IKI+ light blue with a darker blue tube that appears as two parallel lines ascending through the entire height of the tholus; spores 8 per ascus, simple, colourless, broadly elliptical or fusiform.
References: Printzen et al. 2008.
| 1a. | Thallus sorediate, UV+ white, containing lobaric acid …Myochroidea porphyrospoda |
| 1b. | Thallus lacking soredia, UV- or + yellow-orange, lacking lobaric acid …2 |
| 2a. | Areoles mostly lifting from the substrate, often slightly branched, UV-; hymenium with scattered oil droplets; known from near the study area on ericaceous shrubs in subalpine forest, to be sought …[Myochroidea leprosula] |
| 2b. | Areoles not or scarcely lifting from the substrate, not branched, UV+ yellow-orange; hymenium lacking oil droplets …Myochroidea rufofusca |
Myochroidea porphyrospoda (Anzi) Printzen, Spribille & Tønsberg
Thallus light to dark grey, lumpy-areolate, the areoles disintegrating into multicoloured whitish, olive and reddish brown, granular soredia 20-40 (‑50) µ wide; apothecia usually absent, 0.5-0.8 mm wide, reddish brown, with a thin, receding rim; paraphyses with red-brown pigments in a sheath and swollen up to 5 µ at the tip; hypothecium colourless; spores elliptical, 12-14.5 × 6-7 µ.
Reactions: UV+ white.
Contents: Lobaric acid.
Habitat: On smooth or rough bark of conifers and shrubs within the winter snowpack. Mostly upper forested elevations.
Similar Species: Lecidea leprosula has similar apothecia and a similarly coloured thallus, but has tiny squamules and no soredia.
Specimens: Björk 12895.
Local Status: Occasional.
Myochroidea rufofusca (Anzi) Printzen, Spribille & Tønsberg
Thallus darkish olive, of areoles 0.2-0.35 (‑0.5) mm wide, or immersed; apothecia 0.4-0.7 mm wide, mostly clustered or crowded, the rim thin and receding, the disc flat to low-convex, or in old apothecia becoming high-convex, deep darkish red-brown; rim interior colourless or pale orangish brown, the outermost cells enlarged up to 4 µ wide; hymenium 60-75 µ high, pigmented orange brown or dark red-brown in the upper portions; hypothecium colourless or pale yellowish brown; paraphyses weakly to moderately branched and anastomosing; spores 1-celled, broadly elliptical or broadly ovate 5-9 × 3-6 µ, the walls less than 1 µ thick.
Reactions: K- or + yellowish.
Contents: Two or three xanthones, including 2,5,7-trichloro-3-O-methylnorlichexanthone.
Habitat: On acidic bark of ericaceous shrubs and conifers within the winter snowpack. Upper forested elevations.
Similar Species: Somewhat similar to and often growing with Biatora toensbergii, which has a thinner apothecial rim and spores at least 11 µ long.
Specimens: Björk 13783.
Local Status: Occasional.