Description: This humidity-tolerant ‘pin-head’ lichen grows on the wood of decaying stumps. It has a granular, greenish-grey thallus but, most importantly, has long stalks which, when squashed in iodine, turn dark blue. It is a reaction unique to this species. The discs, which are shaped like an inverted traffic cone, have a reddish-brown tinge and a distinctive white dusting on the lower surface of the head. In Ireland, it is known only from County Kerry.

Key Identification Features:

• Discs, reddish brown, inverted cone-shaped with white pruina
• Stalks, dark blue in iodine squash; decaying stumps in humid woods.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Calicium lenticulare at iNaturalist World Species Observations database.