Micarea alectorialica is a species of bark-dwelling, lichen-forming fungus in the family Ectolechiaceae. It was described as new to science in 2014 from the tropical island of Réunion (Mascarene archipelago) in the Indian Ocean. The type collection was made in the , in wet montane ericoid (heather-family) thickets, where it grew on stems of Erica at about 1,890 m elevation. On Réunion it has been recorded mainly from similar high-elevation thickets around 1,900âÂÂ2,000 m, where it is reported to be abundant.
The lichen forms a pale, thallus (to about 5 cm across) in which the small break open into convex soralia (usually up to about 0.6 mm across) that are white to pale greenish. The powdery soredia are roughly 25âÂÂ35 üm wide. Its shiny black apothecia (fruiting bodies) are convex and small (to about 0.7 mm across) and the spores are fusiform, typically 1âÂÂ3-septate (about 17âÂÂ20 à4.5âÂÂ5.6 üm). Chemically, the species is characterized by the presence of alectorialic acid (with a C+ red reaction and K+ yellow, P+ yellow) and it also contains a fatty acid. These features help separate it from most other Micarea species, which rarely produce alectorialic acid. The species epithet alectorialica alludes to this characteristic feature.