ASCOMYCOTA | LECANOROMYCETES > CALICIALES > Physciaceae

Genus Physcia, meaning 'inflated, sausage-like' - from the form of the type species

Common name:            -

Synonym:                    -

Habitat:                         Woodland, wayside trees

Substrata:                     Bark, rarely on rocks and stone

Growth form:                Corticolous (saxicolous)

Thallus:                  Foliose

Apothecia:                    Lecanorine, infrequent

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

Thallus variable, spherical to irregular, usually no more than 3cm across, which is typically smaller than the similar Physcia adscendens, but often growing with other species thereby forming a larger intermixed patch; lobes loosely appressed, long and rather erect, around 1mm wide broadening to 2mm at the tips, with small pseudocyphellae and prominent, long, pale marginal cilia; differs to Physcia adscendens in that the lobes ends are not folded up into a 'helmet-shape', instead, splitting, widening and turning back to reveal rather course, creamy soralia on the lower margins; lobes generally whitish to pale greenish-grey, occasionally more brownish, without pruina; underside not dissimilar colour, with relatively few white to black rhizines.

Apothecia infrequent, but not uncommon, to 2.5mm dia., on short stalks, discs blackish or blackish brown and pruinose.

As previously noted, Physcia tenella and Physcia adscendens are often found growing together, so care needs to be taken particularly with older specimens of Physcia adscendens where the 'hoods' of the 'helmet-shaped' lobes may have been eroded and, thereby, possibly resembling the upturned lobes of this species. Generally, Physcia tenella is slightly darker, with smoother, more appressed lobes.

Although Physcia tenella is just as common and widespread as Physcia adscendens, it's primarily a corticolous species found on the bark of tree trunks and branches, and commonly on twigs, but rarely on other substates such as rock. Specimens found on the twigs of exposed, well-lit, isolated trees, invariably mixed in with other species, are more often fertile, with some authors describing this variety as Physcia tenella forma ramicole.