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All Fungi
Rhizocarpon reductum
Nomenclature
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Family: RhizocarpaceaeGenus: Rhizocarpon
SUMMARY
Thallus effuse or in discrete patches 1-2 cm diam., sometimes coalescing to cover large areas, grey to brown, cracked-areolate, thin to moderately thick, very rarely almost subsquamulose. Areoles 200-400 µm diam., slightly convex or flat. Prothallus usually conspicuous, particularly at the margin, sometimes dominant especially in shaded situations.
Anamorph: not known.
Teleomorph: ascomata apothecia, (200-) 400-600 (-800) µm diam., black, immersed to sessile, flat to slightly convex, with a rough disc, becoming more strongly convex when over-mature. Proper exciple usually well-developed and slightly raised but often excluded in convex apothecia, composed of radiating hyphae, outer cells blue-black, K+ yellow. Epithecium olive-green (K+ blue, N+ red), rarely brown. Hymenium hyaline, 120-140 μm high. Hypothecium mid-to dark-brown. Interascal tissue of narrow pseudoparaphyses ca 1 μm diam., scarcely swollen at the apex, without a strongly delimited pigmented cap. Asci 65-80 × 25-33 μm, clavate to cylindric-clavate, fissitunicate, with a well-developed tholus that is K/I– in the lower part and K/I+ blue near the apex, lacking an ocular chamber, 8-spored. Ascospores 20-35 × 10-15 μm, muriform, (6-) 8-13 (-17) cells in optical section, hyaline, fairly thick-walled, smooth, with a conspicuous gelatinous sheath.
Chemistry: usually C–, K+ yellow, Pd+ orange (stictic acid), rarely K–, Pd– (no lichen substances) or K+ red, Pd+ orange (stictic and norstictic acids).