Thallus horizontalis crustaceous, consisting of loosely aggregated or nearly evanescent granules, c. 0.5 mm diameter, white when dry. Pseudopodetia simple or branched in the upper part. Branches either dichotomous or irregularly bush-like. Pseudopodetia 1.0-1.5 cm high and c. 3 mm broad. Younger parts covered with a continuous algal layer, consisting of minute granules or scales. Color of scales white, later becoming blackened at the base of the pseudopodetia. Basal part of old pseudopodetia often ecorticate. Central column of the young stalks hyaline, while the interior of older stalks is completely black. Pycnidia not observed.
Mature apothecia are absent in all specimens examined, but primordia of apothecia are found terminal at the tip of the stalks.
Phycobiont green, Pleurococcus type.
Cephalodia stipitate on the pseudopodetia (fig. 11), containing Nostoc in the type-specimen and Stigonema in other specimens. Small cephalodia-like structures on the substrate contained algae of the Gloeocapsa type but it seems doubtful, whether they belong to this lichen.
Growing on silicate rock.
RemarksP. vegae can be confused with P. robustus and P. acicularis occurring in the same region. The clearest characteristics of the species, which are lacking in P. robustus and P. acicularis, are the white color of the young pseudopodetia and the black pigment of the central column. P. nigricaule, which also has a white cortex and a black central column is smaller and easily recognized by the globular or peltate shape of its cortex granules.
Distribution (map 14) P. vegae is known from Alaska and the Bering Strait area only.