Galapagos Species Database

Thallus slate gray to grayish black when dry, olive when wet, foliose, adnate, papery thin; outline ± orbicular; lobes distinct, elongate, ± broadened and flattened, regularly spreading (fan-shaped); surface smooth to barely striate, but not distinctly wrinkled, dull; lacking isidia; apothecia common, sessile to shortly stalked, laminal, expanded; disk pale to deep reddish brown, initially concave, flattened with age; margin lecanorine, concolorous with thallus or slightly pallid, with a broad paraplectenchymatous outer thalline exciple and an inner, indistinct, thin, prosoplectenchymatous proper exciple; ascospores ellipsoid to subfusiform, submuriform, 3-5 transversely, and (0)-1 longitudinally septate, 15- 28 x 7-10 µm.

A broad lobed species with sessile apothecia and no isidia, at first glance similar in appearance to L. cyanescens, which roughly has the same size, but is typically densely isidiate and rarely develops apothecia. Easily confused with L. punctulatum, another species that is very similar in size and overall appearance lacks isidia and is typically fertile. Leptogium punctulatum, however, has a two-layered thallus with numerous pits that correspond to attachment points where the two layers adhere to one another. Leptogium azureum was originally confused with L. cochleatum, but all Galapagos specimens lack a distinctly paraplectenchymatous inner exciple and broad paraplectenchymatous hypothecium. Instead the proper exciple and hypothecium of all specimens is thin and prosoplectenchymatous