Parmotrema asperum is a species of saxicolous lichen in the family Parmeliaceae. Found in Brazil, it was described as new to science in 2008. The milky-grey thallus of the lichen is up to 11cm (04inches) in diameter, consisting of irregularly branched lobes measuring 2.0–6.5 mm wide. The lichen is named for the coarse appearance of the thallus.