Psora decipiens

A lichen with a squamulose thallus growing on soil in arid zones, on calcareous substrate, with very striking orange-brown to reddish-brown squamules having a whitish margin that contrasts sharply with the rest, and minute very dark brown to black apothecia located at the margin of the squamules.

Medullary hyphae closely interwoven, hyaline, with a layer of spherical, unicellular algae 10 to 15 µm in diameter.

Asci clavate, eight-spored, 60 to 70 µm long, 12 to 18 µm wide, with biseriate to irregular spore arrangement inside the ascus, and amyloid in Melzer's reagent.

Paraphyses filiform, multiseptate, hyaline, simple, unbranched, 1.5 to 2.5 µm wide, with slight apical enlargements reaching a total width of 3 to 4 µm, covered apically by a very dark brown, almost black amorphous gelatinous mass, and exceeding the height of the asci.

Ascospores ellipsoidal to slightly fusiform, unicellular, smooth, hyaline, thin-walled, 12 to 18.5 µm long, 5.5 to 8 µm wide, containing faint granular content inside.