Lobothallia radiosa

General: Saxicolous placodioid crustose lichen on limestone, forming rosettes with a greyish-green thallus, white growing margin, radiately lobed periphery, and abundant small central apothecia.

Apothecia: Disc-shaped, slightly concave, 0.5-1.3 mm diam., brownish-black with a thick, slightly raised whitish margin.

Asci: Clavate, 8-spored, 60-75 x 16-22 µm, spores irregular to slightly biseriate, strongly amyloid in Melzer's reagent together with the surrounding hymenial gel.

Paraphyses: Filiform, unbranched, multiseptate especially in upper half where they become moniliform/torulose with constricted septa, 1.5-2 µm wide, apices swollen up to 3 µm, projecting distinctly above asci.

Ascospores: Ellipsoid, smooth, slightly thick-walled, unicellular, hyaline, literature reports 10-15 x 6-9 µm (study collection slightly larger, likely postmature), contents homogeneous without guttules.