ASCOMYCOTA | LECANOROMYCETES > LECANORALES > Parmeliaceae

Common name:            Hooded Tube Lichen

Synonym:                      Parmelia physodes

Habitat:                         Ubiquitous

Substrata:                     Bark, primarily, also weathered and dead wood, and as text

Growth form:                Corticolous, lignicolous and saxicolous

Thallus:                  Foliose

Apothecia:                    Lecanorine, but rare

BLS identity rating:        Graded 1/5 (identification should be straightforward)

Thallus rather varied depending on its habitat, typically rosette shaped, 5-10cm or so across or, in other situations, as irregular shaped spreading patches; lobes, 2-3mm wide, hollow, but not tubular as Hypogymnia tubulosa, becoming up- turned and fan-like, the upper surface is generally described as being grey, perhaps with a hint of blue, to greenish-grey, shiny, sometimes with black dot-like pycnidia towards the tips; under-surface light brown at the margin, dark brown to blackish in the centre where it is wrinkled and attached to the substratum.

Apothecia rare, sparce if present, on short thick stalks, discs red-brown with a thin thalline margin.

Ubiquitous, supralittoral to montane; occurring on siliceous trees, rocks, moss, heather [Calluna] stems as well as occasionally on wooden posts or dead trees. The corticolous form described here is the most common, with overlapping and somewhat swollen lobes, whereas specimens found in moist sheltered habitats, such as amongst Calluna, will likely have thinner, more discrete lobes.

It's a widespread holarctic species found right across Britain; also common throughout the Alps where I took this photo.