TYPE. UNITED STATES. Massachusetts, Bristol County. New Bedford, 1874, H. Willey s.n. (US, holotype).
Description.Life form: lichenized fungus
[Modified from Sheard (2010)]
Morphology.Thallus crustose, thin partially within bark, quickly becoming surficial, light to darker gray, areolate; areoles to 0.50 – 0.60 mm wide, sometimes developing raised margins (subsquamulose), finally forming a more continuous thallus; surface plane, matt; margin indeterminate; prothallus absent. Vegetative diaspores soredia, mostly developing from areole margins, 15 – 20 μm diam, concolorous with thallus or somewhat lighter, becoming densely but not continuously sorediate, forming discrete, convex soralia, sometimes with consoredia 30 – 45 μm diam. Photobiont chlorococcoid alga, likely Trebouxia. Ascomata lecanorine apothecia, immersed, becoming broadly attached, sometimes frequent, scattered, rarely contiguous, up to 0.50 – 1.00 mm diam.; disk black, plane, sometimes becoming slightly convex; thalline margin concolorous with thallus, entire, becoming sorediate or in part forming late, growing up around proper exciple, persistent, 0.05 – 0.10 mm wide; proper margin sometimes present, raised.
Ascomatal anatomy.Thalline exciple 35 – 90 μm wide; cortex absent or ~ 5 μm wide, sometimes with epinecral layer ~ 10 μm wide; crystals present in cortex and medulla; cortical cells up to ~ 4.0 μm wide, sometimes pigmented; algal cells to 12.0 – 13.5 μm long. Proper exciple hyaline or light brown, 10 – 20 μm wide laterally, expanding to 30 – 50 μm above. Hypothecium hyaline or light brown, 60 – 100 μm deep; hymenium pale brown or hyaline, 100 – 150 μm high, not inspersed; paraphyses ~2.0 μm wide, strongly conglutinate, tips expanded to 3.5 μm wide, lightly pigmented, immersed in a dispersed pigment, forming a light red-brown epihymenium. Asci ~ 55 x 27 μm, 8-spored. Ascospores Type A development (i.e., apical wall thickening after septum formation), Pachysporaria-type I: (17.5-) 23.5 – 25.0 (-31.0) x (9.0-) 12.5 – 13.5 (-17.0) μm, mean l/w ratio 1.7 – 2.1, lumina Physcia-like or irregularly angular (approaching polygonal) during development, mature spores sometimes slightly constricted at septum; torus usually present, narrow; walls lightly pigmented, smooth.
Conidiomata not seen.
Chemistry. Spot tests: K+ faint yellow, C-, KC-, PD+ cinnabar; secondary metabolites: pannarin and zeorin detected via TLC.
Substrate and habitat. Corticolous and muscicolous on Carya and Acer.
Distribution. North America (northeastern and Appalachian mountains); in North Carolina found in the Blue Ridge ecoregion.
Literature
Sheard, J.W. (2010) The Lichen Genus Rinodina (Lecanoromycetidae, Physciaceae) in North America, North of Mexico. NRC Research Press, Ottowa.