Order: Lecanorales Family: Megalariaceae
Species: Megalaria pulverea
Photos: Killarney National Park, Co. Kerry, SW Ireland.
Sterile specimen identified by John Douglass
Thin, +/- evanescent, greyish to blue-grey, granular thallus with grey-green, yellowish-green or bluish soralia. Pycnidia are absent, apothecia rare, flat or +/- convex, black or brownish with paler margins. Ascus 8-spored, spores 1-septate 10-18 x 4.5-6.5 Ám.
On acidic mossy trunks of oak, ash and willow in old, damp woods. Rare on branches, mossy rocks, coastal soil and calluna stems.
K+ yellow, usually P+ red, sometimes P+ faint yellow or P-, UV-
Similar: Megalaria grossa. Thallus: Chemical reactions negative.
Megalospora tuberculosa. K+ yellow, P-, UV-
Megalaria pulverea November 2009