Protologue Description: Peltigera phyllidiosa Goffinet & Miadlikowska sp. nov.

Peltigerae collinae affinis. Thallus etomentosus, glaber; lobi 0-5-2-0 cm lati, isidiato-phyllidiati. Apothecia revoluta nigra; Ascosporae aciculares, triseptatae. Pycnidia ignota.

Typus: United States of America, Georgia, Rabun County, Southern Appalachians, southeast escarpment of the Southern Blue Ridge, Chattahoochie National Forest, 34°58"N, 83°18'W, lower portion of trail from parking area to top of mountain, mountain slope with mixed hardwood forest with Betula lenta, Quercus rubra and Q. montana, and Magnolia, base of Quercus, 4 October 1997, Goffinet 4561 (DUKE-holotypus; herb. Goffinet, NY, H-isotypi).

Thallus 5-8 cm in diameter, grey to greyish-brown when dry. Lobes 0.5-2.0 cm broad, plane to concave with reflexed or rarely plane or erect margins. Phyllidia present along margin or laminal cracks, branched, becoming dorsiventral, spreading laterally, forming small `cushions' of squamules. Soredia absent. Upper surface smooth, shiny, pruinose near tip of lobes, rarely maculate toward apex, glabrous. Lower surface reticulate, veins distinct, flat to bulging, slightly raised above the interstices, dark brown to pale toward margin; interstices elliptic, white; rhizines simple, rarely fasciculate, up to 5 mm long, concolourous to veins. Cortex paraplenchymatous, up to 45 mµ thick, photobiontic layer containing cyanobacteria (Nostoc) up to 75 µm thick, medulla up to 120 µm thick, and veins up to 150 pm thick. Pycnidia not seen.
Apothecia on short elongate lobes, disc black, scabrose, with either strongly recurved margins or saddle-shaped, up to 7 mm long. Paraphyses linear simple, with swollen apical cells. Asci clavate, 8-spored. Spores acicular, triseptate 40-71 X 2.0-3.5 µm wide.
Name derivation: Peltigera ? phyllidiosa