Stereocaulon pileatum Ach.

    Primary thallus persistent, consisting of granular phyllocladia, 1-3 mm, warted, greyish when moist, dark brown when dry. Pseudopodetia short, 3-5 mm tall, simple, seldom branched, topped with globose piles of soralia, yellow-greenish when moist, grey-greenish when dry. Granular cephalodia with Stigonema rare, brownish, brown-greyish. Apothecia rare, on tip of pseudopodetia, convex, brown-redish, brown. Ascospores markedly elongate, multi-septate, 18-30 x 4-4,5 µm. Photobiont: Trebouxioid. C-, K+ yellow, KC+ violet, Pd+/- yellow. Rare and inconspicuous, on rocks and stones enriched in iron or heavy metals, in dumpsites or quarries (notably of slate quarries), most often in shaded and humid areas, seldom on walls. See Stereocaulon nanodes of which the primary thallus consists of erect phyllocladia, swollen and sorediate, usually with more ramified pseudopodetia.*