TYPE. UNITED STATES. Maryland, Baltimore County, Gunpowder, on rocks along right bank, 7.VI.1910, C.C. Plitt 255 (HBG, lectotype designated by Dibben (1980); NY, US, isolectotypes).

Description. Life form: lichenized fungus.

[Modified from Dibben (1980)] Thallus crustose, epilithic, ash gray to dark gray, thin to moderately thick; margin +/- entire, rarely zoned, often radiately cracked and paler than thallus. Surface verrucose, shiny or matt, predominantly rimose or rimose-areolate; areoles (0.2-)1.4(-3.0) mm diam. Vegetative diaspores absent. Photobiont chlorococcoid alga. Fertile warts thallus-colored, frequent, dispersed or locally crowded and fused (2-3(-4), initially conical becoming flat-topped, sometimes granular or eroded, 0.4-)1.2(-2.5) mm diam. Ostioles 1 or 2-8+ per fertile wart, concolorous or dark beneath, frequently surrounded by a whitish border, level or sunken, scattered or grouped in a central depression, (0.05-)0.2(-0.4) mm diam.  Ascomata pertusaroid apothecia, (1-)2-4(-6+) per fertile wart, (0.34-)0.53(-0.96) mm diam.; hymenium hyaline to pinkish or whitish; hypothecium hyaline or pallid; epithecium hyaline to dark, K- or rarely K+ weakly wine red. Asci clavate or more often cylindrical, (215-)315(-445) x (30-)55(-85) μm, often immature or aborted, (1-)2-spored, uniseriate; ascospores ellipsoid to cylindrical, often immature or aborted, (75-)150(-245) x (25-)45(-75) μm; outer spore wall (2-)5(-12) μm thick, often diffuse or thickest at midplane; inner spore wall (2-)10(-20) μm thick, smooth or externally roughened, laterally radially zoned or channeled; end wall (8-)25(-60) μm thick. Pycnidia not reported.

Chemistry. Cortex UV-, K-, KC-, PD-; medulla K- or + yellow turning red, KC-, C-, PD- or + yellow turning orangish; norstictc, connorstictic, perlatolic and stenosporic acids detected by TLC.

Substrate and Habitat. Saxicolous on acidic rocks.

Distribution. Eastern North America; in North Carolina found in the Blue Ridge and Piedmont ecoregions.

Literature

Dibben, M.J. (1980) The Chemosystematics of the Lichen Genus Pertusaria in North America North of Mexico. Publications in Biology and Geology No. 5, Milwaukee Public Museum Press, Milwaukee. 162 pp.

Erichsen, C.F.E. (1936) Beiträge zur Kenntnis der Flechtengattung Pertusaria. Feddes Repertorium specierum novarum regni vegetabilis 41: 77-101 (original description).