Phytologia 28: 480 (1974).

Basionym: Parmelia bicornuta Müll. Arg., Flora, Regensburg 74, 3: 377 (1891).

Type locality: Brazil, Rio de Janeiro, Leyland (BM - lectotype; G - isolectotype)

Thallus: adnate on bark, whitish mineral grey, 4-6 cm in diameter; lobes sublinear- elongate, 0,7-1,5 mm wide; bulbate cilia dense, strongly inflated, becoming apically branched; upper surface plane, shiny, continuous; lower surface black, densly short rhizinate, the rhizines branched. Apothecia adnate, 1-4 mm in diameter, the exciple ecoronate; spores 8, bicornute, 3-4 X 15- 19 µm.

Chemistry: Cortex K+ yellow, medulla K-, C+, KC+ red, P-, atranorin and lecanoric acid.

Ecology: On trees in open forest.

Molecular data: Genbank

Distribution: Brazil, Database

Note: The most distinctiv feature of this rare species- is the bicornute spores. The other two species in the genus with bicornute spores, B. schiffneri and B. seminulata, have different chemistry and much narrower lobes. It is probably unrelated to lecanoric acid- containing. B. confoederata, a North American endemic which has ovoid spores and narrow lobes (0,5- 1,0 mm wide). Müller measured the spores as listed above in the describtion, but my own examination gave smaller spores, about 8 µm long.