in Divakar, Crespo, Núñez-Zapata, Flakus, Sipman, Elix & Lumbsch, Phytotaxa 132, 1: 33 (2013).
Basionym: Parmelia vexans Zahlbr., Feddes Repert. Spec. Nov. Reg. Veg. 33: 55 (1933).
Type locality: Taiwan, Mt. Arisan, Kainoodai, Asahina 79 (W - holotypus). Not mentioned in checklist.
Type locality coordinates: Data lacking.
Type locality photo: Data lacking.
Type scan: Data lacking.
Molecular barcode: Data lacking.
Thallus: 5 - 12 - 17 cm long, lobes 0.5 - 2 - 4 mm broad, dichotomously or subdichotomously divided, strongly to moderately involute or flat; upper surface pale, slightly to densely isidiate, the isidia to 1 mm, often bearing a lateral, rarely terminal black hair 0.2 - 0.5 - 2 mm long, the isidia becoming sorediate in some Venezuelan specimens, the usually abundant marginal rhizines to 3 - 4 - 6 mm long, simple or branched; lower surface black, brown- or pale-colored at the tips, usually naked but with a few short, usually simple, black rhizines in some. Apothecia very rare, the only one seen 6 mm in diameter; spores 5 - 6 - 8 / 12 - 13 µm, ellipsoid. Pycnidia rare, 0.1 - 0.2 mm in diameter; microconidia ca. 1 / 5 - 7 µm, straight rods.
Photobiont: Data lacking.
Chemistry: Cortex K- yellow; medulla K+ yellow turning red, C-, PD+ yellow turning orange. Atranorin in all specimens. Galbinic acid in 48 (89 %) of the specimens tested by Culberson & Culberson (1981: 295). Four of the six specimens lacking detectable galbinic acid contained a trace of protocetraric acid instead and came from southeast Asia. Protocetraric acid is also a common trace accessory in Everniastrum vexans, being found with galbinic acid in 21 (29 %) of the specimens, one of which also contained a trace of gyrophoric acid. The type contains atranorin, salacinic acid and protolichesterinic acid (Hale fide Culberson & Culberson 1981: 295).
Ecology: On trees and shrubs, on mooses on the ground, rarely on rocks in tropical mountains from 1200 - 3200.
Distribution type: Mexico, Middle and South America, Kenya, Asia.
Taxonomy: Data lacking.
in IF nicht als homonymes Synonym von Hypotrachyna v. erkannt: Parmelia vexans Zahlbr., Feddes Repert. 33: 55 (1933).
in IF: Cetrariastrum vexans Zahlbr. ex W.L. Culb. & C.F. Culb., Bryologist 84(3): 294 (1981).