G. astrapeana G. contristans G. holomeloides G. squalescens Gilbertaria is a genus of lichen-forming fungi in the family Sphaerophoraceae,[1][2] comprising four species of crustose lichens found primarily in arctic and alpine environments.

The genus Gilbertaria was circumscribed in 2022 by Måns Svensson and Alan Fryday, who demonstrated through molecular phylogenetics analysis that several previously misunderstood lichen species formed a distinct evolutionary lineage within the family Sphaerophoraceae.

[4] Prior to the establishment of Gilbertaria, the species now placed in this genus had been variously classified under different genera including Catillaria, Lecidea, and Toninia, reflecting the historical uncertainty about their relationships.

When examined under a microscope, they reveal several unique characteristics: Gilbertaria species frequently grow alongside blue-green algae of the genus Stigonema, which can be found between the lichen's granules or near its reproductive structures.

These lichens show a strong preference for growing on dying or dead moss colonies, especially species of Andreaea and Gymnomitrion, and are often found in seepage areas where water periodically flows over rocks.

G. contristans typically occurs in relatively dry situations on dying bryophytes on sloping rock walls, while G. holomeloides favours more humid conditions and is often found growing directly on the ground.