Thallus slate gray to grayish black, olive when wet, foliose, adnate to ± loose, papery thin; outline ± orbicular; lobes distinct, elongate, ± broadened and flattened, regularly spreading (fan-shaped), composed of two layers owing to the adherence of thin lobes folded upon one another; surface smooth to barely striate, typically spotted with small pits where the two layers of thallus lobes are riveted to one another; lacking isidia; apothecia common, sessile to shortly stalked, laminal; disk pale to deep reddish brown, initially barely concave, soon flattened; margin lecanorine, often pale brownish, rarely concolorous with thallus, with a broad paraplectenchymatous thalline exciple and an indistinct, thin, prosoplectenchymatous proper exciple; ascospores ellipsoid to subfusiform, ends often pointed, muriform, 4-5 transversely, and 1-2(-3) longitudinally septate, 25-39 x 10-14 μm.
Substrate & Ecology: Relatively rare, but possibly overlooked because of its similarity with L. azureum; throughout the moist uplands of islands with higher elevations, occasionally also at lower elevations in the transition zone, but not found in the dry zone.
Distribution: Known from Floreana, Isabela, Santa Cruz, and San Cristóbal Island.
Notes: The two layered lobes with attachment pits are characteristic, but can easily be overlooked.
Specimens examined: Floreana Island: 560 m, on Psidium, Itow 9 (L-40732), COLO no. 192855; Isabela Island: Volcán Alcedo, on top of the crater rim, 0˚27’33”S, 91˚6’49”W, 1051 m, moist upland; disturbed by former grazing of goats therefore scattered trees (Zanthoxylum fagara, Scalesia microcephala, Tournefortia rufo-sericea), on bark, underside of small inclined Scalesia stem (ca. 6 cm in diam.); semi-shaded, wind- and rain-sheltered, 5 Mar 2006, Bungartz 4099, CDS no. 28067. Pinta Island: E-slope of the highest crater, 525 m, in open mossy Zanthoxylum forest, on horizontal branch of Pisonia in shade, 11 Jul 1976, Sipman 136 (L-63612), COLO accession no 297824. San Cristóbal Island: along trail between entrance to Cerro Pelado and Cerro Partido, trail to Ripioso, 0˚51’40”S, 89˚27’38”W, 383 m, transition zone; dense forest on abandoned farmland with old trees of Hippomane mancinella and introduced species such as Psidium guajava, Passiflora sp. and an understory of Chiococca alba and Rubus niveus, on bark, trunk of Psidium guajava (ca. 5 cm in diam.), N-exposed; semi-shaded, wind- and rain-sheltered, 28 Apr 2007, Bungartz 6675, CDS no. 34911. Santa Cruz Island: below and N of Mount Crocker, 650 m, Scalesia pedunculata forest, near the margins of the stands where there is more light and less competition with hepatics, on horizontal branches of Scalesia, 16 Apr 1976, Weber Lich. Exs. 505 (L-63680), COLO no. 297756; below Puntudo, 720 m, on bark, tops of horizontal branches of Scalesia, 18 Apr 1976, Weber s.n. (QCA); Santa Cruz, Camote, Finca of René Valle, close to boundary of the National Park of Galápagos, 0˚38’21”S, 90˚17’53”W, 473 m, Scalesia zone; young and dense forest of Scalesia pedunculata with undergrowth of Chiococca alba, on bark, trunk of Scalesia pedunculata (ca. 10 cm in diam.); shaded, wind- and rain-sheltered, 12 Dec 2006, Bungartz 5555, CDS no. 32996; on tops of horizontal branches of Scalesia; below Puntudo, 720 m, 18 Apr 1976, Weber s.n., CDS no. 10839.
from: Bungartz, F. (2008) Cyanolichens of the Galapagos Islands - The genera Collema and Leptogium. Sauteria15: 139-158.