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Dimelaena californica (H. Magn.) Sheard
Family: Caliciaceae
Dimelaena californica image
Stephen Sharnoff  
Life habit: typically parasitic on Dimelaena radiata and other crustose species and eventually replacing them Thallus: thin to thick, areolate, margin with or without poorly developed radiate-plicate lobes, prothallus: black, present between areoles and around margins of autonomous thalli areoles: plane, often becoming convex, (0.2-)0.6-0.8 mm wide, surface: dark copper-brown, shiny when young becoming dull Apothecia: frequent, cryptolecanorine becoming adnate, sometimes appearing lecanorine, usually one per areole, 0.2-0.6 mm in diam. disc: black, dull, persistingly plane; epihymenium: brown hymenium: hyaline, I+ blue; paraphyses: simple or weakly branched; hypothecium: dark brown asci: cylindrical, 8-spored ascospores: brown, 1-septate, 9-15 x 5-8.5 µm Pycnidia: frequent, immersed, obpyriform conidia: hyaline, simple, bacilliform, 5-6 x 1 µm Spot tests: K± red, C-, KC-, P± orange Secondary metabolites: norstictic acid (chemotype I), stictic acid or stictic acid and norstictic acid (chemotype II) Substrate and ecology: lichenicolous on D. radiata over acidic rocks, including basalt World distribution: southwestern, coastal North America Sonoran distribution: southern California, Guadalupe Island, Baja California, Baja California Sur, from sea level to 400 m. Notes: Dimelaena californica is typically parasitic on, or associated with Dimelaena radiata and other crustose species. It is characterized by the dark thallus with poorly developed lobate margin, the brown hypothecium and its chemistry. Dimelaena californica is distinguished from D. thysanota and D. weberi by its dark brown hypothecium.