Description: With the uncreative nickname of ‘Laurer’s catillaria’ (Catillaria was its previous genus), this species was formerly present in Killarney, County Kerry but is now catalogued as extinct, which is a good enough reason to go out and rediscover it. You could be forgiven for overlooking it as Lecidella elaeochroma f. elaeochroma but at least parts of the thallus of that species react C+ orange. In Ireland, it grew exclusively on oaks in swamp woodlands on limestone. It has a particular niche-preference: rain tracks below knot-holes, especially on old pollarded trees. Thallus is K+ pale yellow.

Key Identification Features:

• Very like some forms of Lecidella elaeochroma f. elaeochroma but thallus entirely C- and exciple grey-black, matt; epithecium dark purple-brown (not blue-green)
• Rain tracks below knot-holes; trees in old-growth woodlands.

Original text submitted by Vince J. Giavarini

Distribution Map from NBN: Megalaria laureri at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Megalaria laureri at iNaturalist World Species Observations database.