Physcia aipolia (Ehrh. ex Humb.) Fürnr.
Lichen aipolius Ehrh. ex Humb., Fl. Friberg: 19 (1793).
Thallus orbicular, rosette-forming to 10 cm diam., closely attached, corticolous. Lobes radiating, to 3 mm broad, discrete to ± imbricate. Upper surface whitish-grey to dark grey, densely white-maculate and sometimes also weakly white pruinose. Lower surface white to pale brown with pale brown to brown rhizines. Apothecia common, often numerous, rounded to ± contorted by mutual pressure, to 3 mm diam., disc often white-pruinose. Ascospores 16-26(-29) × 7-11 µm. Pycnidia immersed. Conidia 4-6 × 1 µm. Chemistry: Cortex and medulla K+ yellow. Atranorin and zeorin.
N: S: As for P. stellaris. Rather poorly collected. Mainly in drier, eastern sites, often on Hoheria angustifolia.
Cosmopolitan
P. aipolia is distinguished from P. stellaris by its white-maculate lobes and the K+ reaction of the medulla.
