Irish lichens

Megalaria grossa
Order: Lecanorales       Family: Megalariaceae

Species: Megalaria grossa

Growth type crustose.
Photos: The Burren, Co. Clare, Glengarriff woods, Co. Cork, Ireland

Thallus pale green-grey or whitish, +/- smooth, often with black prothallus. Large matt-black apothecia, the thick shiny margins excluded as disc becomes convex. The asci are 8-spored, the spores 1-septate, 20-30 x 10-15 Ám. Isidia and soredia are absent. Microscope photographs below.
Thallus: Chemical reactions negative. Hypothecium dark blue-green, K+ green.

Found in old, humid woodlands in West and SW Ireland on nutrient-rich bark of Ash, Field Maple and Hazel.

Similar: M. pulverea Thallus K+ yellow, P+ red, yellow or negative

Megalaria grossa

Megalaria grossa

Microscope photographs
Megalaria grossa, spores

Megalaria grossa, asci
Megalaria grossa. April 2009 and May 2012

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