Sporodophoron cretaceum (Hue) Ertz & Frisch = Schismatomma cretaceum (Hue) Laundon

    Thallus crustose, 5-12 cm across (but sometimes much larger), thick, uneven, powdery owing to soralia that may cover the whole thallus, whitish when dry, cream-pink when moist. Apothecia unknown under our climate.  Photobiont: Trentepohlia. C- with pure sodium hypochloride  but C+/- faint pale yellow with bleach containing washing soda, K+ yellow, KC+ yellow, Pd- (though sometimes slightly yellow on a fresh thallus in case of photobiont exposition after scratching). Thermophilic species, rare in our prospection area, on dry bark of oaks (Quercus) exposed to sun. Very close to Schismatomma niveum that is  C-, K-, Pd+ yellow-orange and from Schismatomma quercicola of which  the thallus is greyish and C-, K-, Pd+ orange with scattered soralia.*