Carroll Co., on bark of Juglans nigra. Pyxine sorediata (Ach.) Mont. [Physciaceae] Skorepa et al. (1977) – Garrett Co., on oak. Skorepa et al. (1979) – on bark. Biechele (2002) – lower eastern shore of Maryland. E.G. Worthley Herbarium – Frederick Co.; Baltimore Co., growing on a sterile crust, Pertusaria? E.C. Uebel Herbarium – Baltimore Co., Liberty Reservoir, on tree root; Ridge Road, on bark Norway Maple. Lendemer & Knapp (2007) - (1. Millington), (2. Idylwild), (4. Sharptown) Pyxine subcinerea Stirton [Physciaceae] E.C. Uebel Herbarium – Prince George's Co., on oak bark; Baltimore Co., on maple bark. Ramalina americana? Hale [Ramalinaceae] Biechele (2002) – lower eastern shore of Maryland. Ramalina fastigiata (Pers.) Ach. [Ramalinaceae] Skorepa et al. (1977) – Worcester Co., on branches of deciduous trees. Skorepa et al. (1979) – on bark. Ramalina willeyi R. Howe [Ramalinaceae] Skorepa et al. (1977) – Worcester Co., on branches of deciduous trees. Biechele (2002) – lower eastern shore of Maryland. Ramonia microspora Vězda [Gyalectaceae] Lendemer & Knapp (2007) - (2. Idylwild) Rhizocarpon concentricum (Davies) Beltr. [Rhizocarpaceae] E.G. Worthley Herbarium - Garrett Co., Swallow Falls State Forest, on sandstone. Rhizocarpon eupetraeum (Nyl.) Arnold [Rhizocarpaceae] Syn.: Rhizocarpon intermedium Degel. Skorepa et al. (1979) – on acidic rock. Rhizocarpon geographicum (L.) DC. [Rhizocarpaceae] Skorepa et al. (1979) – on acidic rock. Rhizocarpon obscuratum (Ach.) A. Massal. [Rhizocarpaceae] Skorepa et al. (1977) – Baltimore Co., on rock outcrop. Skorepa et al. (1979) – on acidic rock. Rhizoplaca chrysoleuca (Sm.) Zopf [Lecanoraceae] Syn.: Lecanora rubina (Vill.) Ach.; Lecanora chrysoleuca (Sm.) Ach. Skorepa et al. (1977) – Montgomery Co., on rock ledges. Skorepa et al. (1979) – on acidic rock. E.G. Worthley Herbarium - Frederick Co., Mt. Catoctin Park; Montgomery Co., Great Falls, on rocks. Rimelia subisidiosa (Müll. Arg.) Hale & Fletcher [Parmeliaceae] Syn.: Parmelia subisidiosa (Müll. Arg.) C.W. Dodge Skorepa et al. (1979) – on bark. Rinodina applanata H. Magn. [Physciaceae] Skorepa et al. (1979) – on bark. Rinodina ascociscana Tuck. [Physciaceae] Skorepa et al. (1979) – on bark. Rinodina exigua (Ach.) Gray [Physciaceae] Skorepa et al. (1979) – on bark. Rinodina ochrocea Willey ex Fink [Physciaceae] Skorepa et al. (1979) – on acidic rock. Rinodina oxydata (A. Massal.) A. Massal. [Physciaceae] Skorepa et al. (1979) – on acidic rock. Rinodina papillata H. Magn. [Physciaceae] Skorepa et al. (1979) – on bark. Rinodina subminutaH. Magn. [Physciaceae] Skorepa et al. (1979) – on bark. Sarcogyne clavus (DC.) Kremp.