Pertusaria pertusa var. rupestris (DC) Dalla Torre & Sarnth.
Pertusaria rupestris (DC) Schaer.
Thallus crustose, rather thick, cracked-areolate, verrucose, warts large and rounded, globose, irregular and sometimes distorted, very pale greyish. Apothecia, 3-10 per fertile wart, punctiform or coma-shaped, disc blackish. Ascii 2-4-spored. Ascospores ovoid, thick walls, very large, 150-250 x 40-80 µm. Thallus: C-, K+ more or less bright yellow, KC+ yellow Pd+ red-orange. Rare variety, differing from the canonical type by its habitat: neutral to weakly acid rocks. N.B. Near the seashore, easily mistaken with fertile specimen of Pertusaria pseudocorallina but the latter has a thallus tinged pink, more regular fertile warts, less numerous punctiform apothecia and is K+ yellow > red. N.B. See Pertusaria pertusa var. rupestris forma whose thallus shows yellowish tones and which is probably a chemoform.