Caloplaca crenulatella
Xanthocarpia crenulatella (Caloplaca crenulatella)

Growth type crustose
Chemical results: Apothecia K+ red/purple

Can be frequent on flat concrete and mortar including drain covers, untreated patios and disused runways.

The greyish-yellow thallus is usually thin and rimose but can vary from almost absent to subsquamulose. Crowded apothecia, the yellow-orange discs with slightly paler margins. Spores 15-18 x 6.5-8.5 Ám, the septum less than 1/8 spore length. Microscope photograph below.

Similar: Caloplaca flavovirescens is larger, spores with wide septum


Caloplaca crenulatella

Caloplaca crenulatella

Microscope photograph
Caloplaca crenulatella
Caloplaca crenulatella
Wimborne Minster, Dorset. March 2017

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