Cora arcabucana is a species of basidiolichen in the family Hygrophoraceae. It was formally described as a new species in 2016 by Manuela Dal Forno, Camilo RodrÃÂguez, and Robert Lücking. The specific epithet arcabucana refers to the type locality in the Arcabuco, (Boyacá, Colombia). The lichen grows on the twigs of shrubs and small trees in montane rainforests at altitudes between . Cora davidia is a closely related species.
Cora arcabucana is a basidiolichen in the family Hygrophoraceae (order Agaricales). It was described in 2016 by Bibiana Moncada, Camila RodrÃÂguez, and Robert Lücking from material collected near the municipality of Arcabuco in the Boyacá highlands of Colombia. The specific epithet, arcabucana, commemorates this type locality. ITS rDNA data position the species in a well-supported subclade that also contains C. davidia and C. garagoa, but morphological and ecological differencesâÂÂparticularly its aeruginous-green thallus, sparse soredia, and narrower, more branched papillaeâÂÂsupport its recognition as a separate taxon.
The thallus is epiphytic and foliose, forming rosettes up to 3 cm across on twigs and small branches, usually overlying mats of bryophytes. It consists of three to seven semicircular, adjacent to sub-imbricate lobes, each 0.5âÂÂ2 cm long and wide. Lobes branch freely, ending in numerous terminal lobules separated by short radial sutures. When fresh the upper surface is aeruginous green and even; as it dries, faint rugosity appears but no concentric colour bands develop. The rolled-in () margins are greenish-grey, glabrous to sparsely , and bear scattered soredia. The lower surface lacks a cortex () and shows a felty-arachnoid medulla that is greenish-grey when fresh, turning white-grey in the herbarium.
Cross-sections are 170âÂÂ250 micrometres (üm) thick. The upper cortex, 70âÂÂ100 üm, is viaduct-shaped and overlies an 80âÂÂ100 üm layer of anticlinal hyphae; both zones are composed of 4âÂÂ6 üm-wide hyphae. The , 50âÂÂ100 üm thick, is aeruginous green, and the medulla, 30âÂÂ50 üm thick, is strongly hydrophobic and bears numerous branched, coralloid papillae 2âÂÂ3 üm wide; clamp connections are absent. The hymenophore is corticioid and completely , forming confluent, cream-white patches that can cover up to 2 à10 mm on the lower surface. Sections (20âÂÂ30 üm thick) show a palisade of basidioles (20âÂÂ30 à5âÂÂ6 üm) and scattered four-spored basidia (25âÂÂ35 à5âÂÂ6 üm); basidiospores have not been seen. Thin-layer chromatography detected no secondary metabolites.
Cora arcabucana occurs in montane rainforest between 2,500 and 3,000 m elevation on the northern Andes of Colombia. It grows epiphytically on shaded to semi-exposed twigs of shrubs and small trees, often in association with bryophyte mats. Its strongly hydrophobic medulla and adnate, confluent hymenophore may facilitate rapid shedding of excess moisture in these cool, humid forests.