Description: This crustose bark epiphyte is similar to Lecanora chlarotera (discs to 1.5mm diam.). It differs in that it has some of its red-brown, frilly-edged discs expanding to almost twice the normal size (2.0-3.0mm diam.) of that species and has white swollen rims which appear inflated like an inner tube, hence its knockabout name ‘Lecanora innertube-escens’. If tested with Pd the rims turn Pd+ deep yellow-orange. It grows mostly on smooth bark in woodland situations, but is not common. In Ireland, the species is widely scattered.

Key Identification Features:

• Thallus smooth, discs red-brown, large with inflated, frilly rims — like a jam tart with a thick pastry crust; rims Pd+ deep yellow orange
• Deciduous smooth-barked trees.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Lecanora intumescens at iNaturalist World Species Observations database.