Rhizocarpon subgeminatum Rhizocarpaceae
Rhizocarpon subgeminatum

Growth type crustose. BLS conservation evaluation: LC NS
Chemical results negative. Epithecium olive-green, K- (intensifying green)

Infrequent (but probably under-recorded) on +/- nutrient-enriched siliceous rocks. Photographs below on slate roof tiles.

Areolate pale to dark brown thallus, the areoles small (to 1mm diam), scattered or contiguous. Black, non-pruinose apothecia, the asci 1-2(-4) spored, spores muriform, 30-50 x 20-28 Ám, persistently colourless or becoming slightly green with age. Micrographs below.

Similar: R. geminatum, epithecium K+ purple-red, spores dark green-brown


Rhizocarpon subgeminatum

Rhizocarpon subgeminatum

Rhizocarpon subgeminatum

Micrographs
Rhizocarpon subgeminatum

Rhizocarpon subgeminatum

Rhizocarpon subgeminatum
Rhizocarpon subgeminatum
Photographs: Wimborne, Dorset. November 2014

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