Thallus: crustose, thick, areolate, areoles sometimes "stalked", sublobate at periphery, up to 0.8-1.4 mm wide, plane surface: light to dark gray, dull or shiny; margin: determinate; prothallus: lacking; vegetative propagules: absent Apothecia: innate, frequent, sometimes contiguous, up to 0.55-1 mm wide disc: black, sometimes pruinose, plane, sometimes becoming convex and fissured thalline margin: concolorous with thallus, often confluent with areole margin, 0.05-0.1 mm wide, entire or rarely becoming excluded; excipular ring: absent thalline exciple: 80-120 µm wide; cortex: 15-20 µm wide; epinecral layer: 15-30 µm wide; cortical cells: up to 3.5-5.5 µm wide, pigmented; algal cells: up to 13-28 µm in diam. proper exciple: hyaline, 10-20 µm wide laterally, expanding to 25-40 µm at periphery hymenium: 90-100 µm tall; paraphyses: 2.5-3 µm wide, not conglutinate, with apices up to 5-7 µm wide, darkly pigmented, penultimate septa also pigmented, forming a dark brown epihymenium; hypothecium: hyaline, 80-130 µm thick asci: clavate, 55-70 x 22-28, 8-spored ascospores: brown, 1-septate, broadly ellipsoid, type A development, Bicincta-type, (17.5-)2021.5(-24) x (9.5-)11-12(-14) µm, young spores often inflated at septum, becoming waisted when overmature, lumina angular at first, becoming rounded, pigmented band around cells usually very light or absent; torus: absent; walls: not ornamented Pycnidia: not seen Spot tests: all negative Secondary metabolites: not tested. Substrate and ecology: on limestone and calcareous sandstone, collected once on Juniperus wood, at elevations of 1230-2130 m World distribution: endemic to western United States, Utah and ranging into southeastern California Sonoran distribution: only from San Bernadino County, California. Notes: Rinodina constrictula is unfortunately named since its Bicincta-type spores are usually inflated at the septum and only constricted when overmature. Such spores predominate in the holotype. It is most likely to be confused with young or poorly developed specimens of R. castanomela, that typically has a brownish, subumbilicate thallus, and significantly smaller spores.