Sticta arbuscula is a species of foliose lichen in the family Peltigeraceae. Found in the South American Andes, it was formally described by Bibiana Moncada and Robert Lücking in 2012. The type specimen was collected in Chingaza National Natural Park (Cundinamarca, Colombia) at an altitude of 3430m (11,250feet). The lichen is found in the Andes of Colombia and Ecuador, at elevations between 3000and, where it grows on bark of twigs and stems. It typically associates with bryophytes from the family Lejeuneaceae and the genera Plagiochila, Metzgeria, Jubula, and Omphalanthus. The specific epithet arbuscula refers to the characteristic arbuscular isidia–branched with a stalk at the base.