Hyperphyscia forms a tightly attached, leaf-like crust that spreads outward in a
rosette. Viewed from above, the individual lobes radiate in shallow, overlapping tiers and are seldom more than a millimetre or two wide. Their surface is dull and free of any frost-like bloom (), ranging in colour from pale brownish-grey to dark brown. The lower surface is much paler and bears only a scattering of very short, almost hidden
rhizines that anchor the thallus to bark or stone. Internally, the upper is built of roughly cube-shaped cells with cavities three to seven
micrometres across, while the lower cortex is restricted to the lobe tips; there it consists of tightly woven brown
hyphae whose minute cells merge into the substrate. Some species develop granular
soralia—tiny eruptions that release powdery
propagules for vegetative dispersal. The
photosynthetic partner ) is a
green alga of the
Trebouxia type.
Sexual reproduction takes place in disc-shaped
apothecia (fruiting bodies) that sit directly on the upper surface. Each is brown, and lacks any whitish dusting, while its rim is made from the same fungal–algal tissue as the rest of the thallus (a ). A pale-brown covers the colourless
hymenium beneath; this spore layer turns blue in iodine, a reaction lichenologists use for identification. The hymenium is threaded with slender
paraphyses that branch near the top and end in club-shaped tips capped by a thin, dark-brown pigment. The
asci are narrow, eight-spored and conform to the
Lecanora type; their spores mature to a single-septate, thick-walled brown form typical of many members of the family
Physciaceae. Asexual spores are produced in immersed
pycnidia whose otherwise colourless walls are ringed by a brown zone at the pore; they release thread-like
conidia formed on short, barrel-shaped cells. Chemical tests have yet to detect lichen acids in the genus, although some species contain traces of the orange pigment
skyrin, visible only under the microscope or by
chromatography. ==Species==