A foliose species with a grey or dark brown, single-lobed thallus that appears rather thin and fragile. The thallus is wrinkled and the wrinkles become stronger towards the raised centre where they form a pronounced, sharp-edged network that is usually white pruinose. The apothecia have black discs that may be gyrose.
Medulla: C+ red, K+ yellow turning red.
In Scotland, Umbilicaria proboscidea is widespread in the Highlands where it grows on well-lit, coarse-grained, siliceous rocks. BLS distribution map
scottishlichens.co.uk 