Irish lichens

Dimerella lutea

Order: Gyalectales       Family: Coenogoniaceae

Species: Dimerella lutea

Growth type crustose.
Photos: On shaded Willow. The Gearagh, Co. Cork, SW Ireland.

Thallus thin or evanescent, light greenish-grey. Apothecia yellow-orange with paler margins, can appear +/- translucent in very wet conditions, possibly seasonal. Pycnidia are occasional, pale yellow. Ascus 8-spored. Spores colourless, 1-septate, 8-11 x 2.5-3.5 Ám. Microscope photographs below.
Chemical reactions negative.

Occurs on moss and bark on deciduous trees in shady, damp old woodland.

Similar: Dimerella pineti has smaller pinkish-white apothecia.
Caloplaca species are K+ red.

Dimerella lutea

Dimerella lutea

Dimerella lutea

Microscope photographs
Dimerella lutea, microscope photograph

Dimerella lutea, ascus and spores

Dimerella lutea
Dimerella lutea. September 2009

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