Myriolecis invadens
Thallus partly superficial, indistinct and sometimes evanescent, crustose, more evident around apothecia, pale grey to greenish grey, often with distinct bluish pigment.
Anamorph: not known.
Teleomorph: ascomata apothecia, 0.4–1.0 mm diam, occurring singly or clustered, sessile or constricted at the base, flat when mature; disc plane to convex, smooth, yellowish brown to blackish or blueish black, slightly to heavily pruinose; margin smooth or rough, entire, even, uniform, pruinose, paler than thallus and paler than disc, white or grey, sometimes indistinct. Thalline exciple 160–170 μm thick, corticate, with algae densely filling the area below the cortex. Hymenium hyaline, 45–65 μm high; subhymenium indistinct; hypothecium hyaline or yellow (more intense in K), 50–100 μm high, composed of adglutinated hyphae. Interascal tissue of paraphyses, simple or dichotomously branched at tips, slender or thickened, not or slightly expanded apically, often pigmented at the top, free in K. Epithecium yellowish or shades of brown or olive, sometimes partly blueish green, sparsely granular between paraphysis tips, the granules soluble in K. Asci clavate, 8-spored. Ascospores hyaline, simple, broadly ellipsoidal, 9–12 × 6–7.5 μm, length/breadth ratio 1.4–2.0:1.
Chemistry: apothecial margin K– or K± yellow, C– or C+ yellow, KC+ yellow, PD–; disc K– or K± yellow, C–, KC± yellow, PD–; apothecia UV– or some apothecia UV+ yellowish.
Not evaluated by Woods & Coppins (2012), but listed as Nationally Rare.
Part of the Myriolecis (Lecanora dispersa) aggregate. Similar to M. semipallida but with a dark brown to blackish disc that is often heavily pruinose, and often a more distinct thallus.
In GB&I, known from Scotland (E Perthshire). Widely distributed in Asia, Europe and North America.
In GB&I, amongst Myriolecis dispersa on slightly calcareous sandstone, in a churchyard. The species frequently overgrows or is parasitic on other lichens.