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Micarea misella (Nyl.) Hedl.
Family: Pilocarpaceae
[Biatora misella (Nyl.) H.G. Falk,  more]
Micarea misella image
André Aptroot  
Thallus: crustose, effuse, usually immersed in the substrate, occasionally better developed convex areoles surface: white to pale gray, smooth but lacking well-defined cortex Apothecia: sessile, 0.1-0.3 mm in diam. disc: black, strongly convex, epruinose proper exciple: poorly developed, but often visible as a dark brown (K+ violet) zone, composed of very narrow (<1 µm), radiating, branched and anastomosing hyphae epihymenium: dull green and K+ violet hymenium: 25-35 µm tall; paraphyses: few, sparingly branched except near apices, <1 µm wide, not capitate although widening to c. 1.5 µm at apices; hypothecium: hyaline, 45-70 µm thick asci: clavate, 25-35 x 7-10 µm, 8-spored ascospores: hyaline, simple, ellipsoid, 7-9.5 x 2-3 µm Pycnidia: usually present, immersed (c. 40 µm in diam.) to emergent to stalked (70-320 µm tall), black conidia: composed of two types: i) mesoconidia, simple, 3.5-5 x 1.5-(1.7) µm; ii) microconidia, simple, 3.8-6 x 0.6-0.8 µm Spot tests: red ( in section), KC+ red, P- Secondary metabolite: gyrophoric acid, although sometimes in small amounts. Substrate and ecology: usually on conifer wood World distribution: probably widespread in Europe, eastern and far western North America, and also known from Brazil Sonoran distribution: known only from two collections in Arizona (Gila & Pima Cos.) on Pinus ponderosa and Juniperus deppeana. Notes: Micarea misella is similar to M. denigrata but usually with immersed thallus and simple ascospores. The microconidia occur in immersed pycnidia.