Hypogymnia physodes Dark Crottle

A very common foliose lichen with a grey-green, lobed thallus. The lobes often turn up and usually have clusters of powdery soredia on their underside. Black dots (pycnidia) are also usually eveident near the tips of the lobes. It grows on trees, wooden posts and benches, moss, heather, rock and other substrates. It is resistent to sulphur dioxide pollution and likes acidic substrates. As air quality has improved it seems to be becoming less common.

Listed by Alan Orange in Flora of Glamorgan (Wade et al, 1994)