Description: Thallus leprose, soft and spongy, pale green, bluish white to pale blue-grey, rarely bluish green, usually diffuse, without marginal lobes, or, more rarely, faintly sublobate at margin, composed of soredia-like granules forming a thick, powdery crust. Granules (25-)60-80(-120) μm in diam, often loosely gathered into up to 500 µm wide aggregates, with abundant projecting, never clam-shaped, short hyphae loosely connecting the granules. Medulla thick, white, the hyphae 1.5-5 µm thick. Hypothallus composed of tightly arranged hyphae; rhizohyphae not forming a well-developed waft. Photobiont chlorococcoid, the cells spherical, up to 21 µm in diam. Spot tests: K+ yellow or K-, C-, KC- or KC+ yellow, P+ orange, UV- or UV+ brown-red. Chemistry: atranorin and stictic acid, and variable amounts of constictic acid and zeorin.
Note: one of the most common species of the genus in Italy, found in the lower parts of trunks, but also on siliceous to weakly calciferous rocks, lignum, soil and mosses, also occurring in rather polluted areas and on surfaces wetted by rain. This species was mostly called L. lobificans, which is a different species, whose type proved to be identical with L. santosii (Lendemer 2013).
Growth form: Leprose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)