Arthoniaceae Q Arthonia molendoi # Lichenicolous, photographs on Xanthoria parietina N.B Images are probably of the very similar Arthonia parietinaria Arthonia molendoi details: Scattered distribution, occurs on Caloplaca and Xanthoria species. Groups of 1-5 convex black apothecia (0.1-0.3mm), epithecium black, hypothecium hyaline or straw-coloured. Asci 4-8 spored, spores 1-septate, constricted at septum, cells unequal, 8-11 x 4-6 µm. Micrograph below. Similar: A. epiphyscia is occasional on Physcia adscendens and P. dubia. Arthonia phaeophysciae occurs on Phaeophyscia spp.

Microscope photograph

Arthonia molendoi
On Xanthoria parietina. Shell Bay, Dorset. December 2013