Arthonia beccariana

Crustose endolithic no-lichenized, epiphytic on smooth barks near the coast.
Note: ascomata dispersed, slightly elongate and branched or simple:

Spores muriform with 7-8 transverse and with 2-3 longitudinal septa, intially hyaline but becoming brown:

Asci broadly clavate to subblobose:

Red crystals K- in the ascoma.
Forophyte: Pistacia lentiscus
Altitude: 2 m
Municipality: El Ejido