Dimelaena radiata
Mountain lichen
This gorgeous placodioid-crustose lichen has a thallus that grows in rounded rosettes with pleated, radiating marginal lobes and an areolate center. It comes in 2 color morphotypes: one which is pale gray due to a thick layer of pale pruina, and a second where only the outer lobes are pruinose so the majority of the thallus is brownish-yellow in color. Its apothecia start out immersed in the thallus with only a thin margin surrounding the black disc, but as they grow the margin becomes thicker and the apothecia become level with the thallus surface. D. radiata has an oddly disjunct distribution, and can be found in the Mediterranean and northern Africa, Macaronesia, and western North America. It can be found on siliceous rock in bright, dry habitats.
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