Cora arachnodavidea is a species of basidiolichen in the family Hygrophoraceae. It was formally described as a new species in 2016 by Bibiana Moncada, Manuela Dal Forno, and Robert Lücking. The specific epithet alludes to the arachnoid surface of the thallus, and also refers to mycologist David Leslie Hawksworth. The lichen is only known to occur in the páramo of Guasca in Colombia, where it grows on the ground in sheltered places between plants and bryophytes.
Cora arachnodavidea is a basidiolichen in the family Hygrophoraceae (order Agaricales). It was formally described in 2016 by Bibiana Moncada, Manuela Dal Forno, and Robert Lücking from material collected in the páramo of Guasca, near Bogotá, Colombia. The epithet combines the lichen's densely (cob-webbed) upper surface with the given name of lichenologist David Leslie HawksworthâÂÂitself derived from the Hebrew "beloved". ITS rDNA data place the species in the same broad clade as C. cyphellifera and C. arachnoidea, but phylogenetic analyses indicate that C. arachnodavidea and the glabrous C. cyphellifera form an unsupported sister pair, collectively distinct from the epiphytic C. arachnoidea.
The thallus is terrestrial, forming a foliose rosette up to 7 cm across on soil between bryophytes or at plant bases. It consists of three to five semicircular , each 1âÂÂ3 cm long and wide, sparsely branched and lacking obvious radial sutures. Fresh lobes are olive-brown to olive-grey with pale concentric zones; rolled-in () margins bear conspicuous white hairs. When dry the upper surface becomes and broadly , while the lower surfaceâÂÂlacking a (it is )âÂÂshows a whitish, felty medulla.
In section the thallus is 350âÂÂ450 micrometres (üm) thick. A diffusely viaduct-shaped upper cortex (30âÂÂ50 üm) overlies a 100âÂÂ150 üm zone of spaced, anticlinal hyphae. Tufts of agglutinated hyphae form stout setae, 200âÂÂ300 üm long and 30âÂÂ50 üm broad at the base. The is 100âÂÂ200 üm thick (orange-brown above, olive-green below). The is Rhizonema andinum, a filamentous cyanobacterium in the family Nostocaceae. The medulla is 70âÂÂ100 üm thick and emits hyphae 3âÂÂ5 üm wide. No clamp connections are present.
The hymenophore is : rounded to irregular, sessile depressions 3âÂÂ5 mm in diameter with cream- to pale orange-brown surfaces and felty, involute margins. Sections show a 200âÂÂ250 üm thick structure supported by a thickened medullary base; the hymenium contains abundant palisade-like basidioles (40âÂÂ50 à5âÂÂ7 üm) and scattered four-spored basidia (25âÂÂ35 à5âÂÂ7 üm). Basidiospores have yet to be observed, and thin-layer chromatography has detected no secondary metabolites.
The species is known only from the páramo of Guasca, Cundinamarca Department, Colombia (roughly 3,220 m elevation). It grows on the ground in lightly sheltered microsites among bryophytes and herbaceous plants, where frequent mist and rapid drying cycles characterise the high-Andean environment.