Thallus pale to dark gray when dry, olive green when wet, foliose, loosely attached, thin; outline irregular; lobes folded and contorted when dry, inflated and dome-shaped when wet; surface smooth when wet, indistinctly striate or wrinkled when dry, dull to ± shiny; lacking isidia; apothecia abundant, immersed at the apex of the dome-shaped thallus lobes; disk pale to deep reddish brown, initially concave, soon flattened; margin lecanorine; thalline exciple concolorous and confluent with the thallus, of several thick, paraplectenchymatous cell layers; proper exciple indistinct, in section thin and prosoplectenchymatous; ascospores ellipsoid to broadly ellipsoid, with blunt or ± tapered ends, muriform, 4-5 transversely and 1-2 longitudinally septate, 22-30 x 10-15 μm.
Substrate & Ecology: Rare; currently known only from the Scalesia-Zone, from twigs and branches of the endemic tree Scalesia pedunculata and the native shrub Chiococca alba.
Distribution: New to the Galapagos; only known from Santa Cruz Island.
Notes: The thalli with inflated dome-shaped lobes and apically immersed apothecia can hardly be confused with any other Leptogium species of the Galapagos. Dry specimens may be mistaken for the plicate thalli of L. phyllocarpum, a species that, however, has a much thicker, strongly rugose thallus and more commonly grows in the dry rather than the humid zones of the islands.
Selected specimens: Santa Cruz Island: along the road to Baltra, S of Los Gemelos, 0˚38’43”S, 90˚20’4”W, 741 m, Scalesia zone; Scalesia pedunculata forest with undergrowth of scattered Chiococca alba and abundant ground cover (Valeriana chaerophylloides, Diodia radula and ferns), on bark of trunk of Scalesia pedunculata (ca. 15 cm in diam.), E-exposed; shaded, wind- and rain-sheltered, 30 Sep 2006, Bungartz 5526, CDS no. 32867; Cerca la vía sector los Gemelos, 0˚38’54”S, 90˚40’6” W, 661 m, Zona húmeda, sobre corteza, Scalesia penduculata, altura al pecho, 4 Jan 2007, Nugra 283, CDS no. 33199.
from: Bungartz, F. (2008) Cyanolichens of the Galapagos Islands - The genera Collema and Leptogium. Sauteria15: 139-158.