Cora caraana is a rare species of basidiolichen in the family Hygrophoraceae. It was formally described as a new species in 2016 by Robert Lücking, Suzana Maria de Azevedo Martins, and Fabiane Lucheta. The specific epithet caraana refers to the type locality in Caraá (Rio Grande do Sul). It is only known to occur at this location, where it grows as an epiphyte on tree branches in mountainous rainforests. It forms rosettes up to 7 cm across with blue-green that have smooth surfaces and light grey rolled-in edges, producing cream-colored reproductive patches arranged in faint concentric arcs on the underside.
Cora caraana is a basidiolichen in the family Hygrophoraceae (order Agaricales). It was described in 2016 by Robert Lücking, Josy Martins, and Fernanda Lucheta from a specimen collected in the Caraá Environmental Protection Area (Rio Grande do Sul, Brazil). The epithet, caraana, refers to this type locality. Internal transcribed spacer DNA sequence data place the species in a clade that also contains C. verjonensis (Colombia) and C. viliewoa (Costa Rica), clearly apart from the morphologically similar Bolivian species C. boleslia.
The thallus of Cora caraana is epiphytic and foliose, forming rosettes up to 7 cm across on shaded branches clothed with hepatic mats. It comprises five to ten semicircular , 0.5âÂÂ1.5 cm wide and 0.5âÂÂ1 cm long, separated by short, indistinct radial sutures. Fresh lobes are bluish-green (aeruginous) with a smooth, surface and thin, rolled-in () light-grey margins; herbarium material turns grey. The lower surface lacks a () and shows a felty-arachnoid medulla that is green-grey when fresh and bluish-grey when dry.
Sections are 150âÂÂ200 micrometres thick. A compact upper cortex 10âÂÂ20 üm deep overlies a 40âÂÂ50 üm zone of anticlinal hyphae; both layers consist of 4âÂÂ5 üm-wide hyphae. The is 50âÂÂ100 üm thick and deep aeruginous; the medulla, 30âÂÂ50 üm, is hydrophobic and bears scattered -to- hyphae 2âÂÂ3 üm wide. Clamp connections are absent.
The hymenophore (the fertile spore-bearing surface) is -, forming cream-coloured, concave patches 1âÂÂ2 mm long and 1âÂÂ5 mm broad that align in faint concentric arcs beneath the lobes. Sections (40âÂÂ70 üm) reveal abundant -like basidioles (20âÂÂ30 à5âÂÂ6 üm) and scarce four-spored basidia (20âÂÂ35 à4âÂÂ6 üm); basidiospores have not been recorded. Thin-layer chromatography detected no secondary metabolites.
As of its original publication, Cora caraana was known to occur only at its type locality (roughly 410 m elevation) in the southernmost outliers of the tropical montane Atlantic Forest of Rio Grande do Sul, Brazil. It grows epiphytically on shaded tree branches, partly overgrowing liverworts, in a humid, evergreen rainforest microclimate characterised by high rainfall, diffuse light, and frequent mist.