Description: This is a widespread species of acid, siliceous rock in the Irish uplands. It is most easily confused with Lecidea lactea and L. confluens but L. lapicida has a pale grey (never dark grey like L. confluens) crustose thallus and is K+ yellow (K+yellow-red in L. lactea and K- in L. confluens). The lichenicolous lichen Cecidonia umbonella grows on this species.

Key Identification Features:

• Thallus K+ yellow, pale grey or slightly ferruginous, prothallus black, discs black (mostly 0.5-1.2mm diam.)
• On acid rocks such as granite, quartzite and schist.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Lecidea lapicida at iNaturalist World Species Observations database.