Hypotrachyna obscurella (Vain.) Hale

Hypotrachyna obscurella

Parmelia gracilescens f. obscurella Vainio, 1890:54. [Type collection: Carassa, Minas Gerais, Brazil, Vainio 1180 (TUR, lectotype; BM, isolectotype).]

Thallus very closely adnate to rocks, dark mineral gray, 4–6 cm broad; lobes sublinear, short, crowded, 1–1.5 mm wide; upper surface plane, shiny, cracked transversely with age, pycnidia numerous, isidia and soredia lacking; lower surface moderately rhizinate, the rhizines sparsely dichotomously branched. Apothecia common, adnate, 1–2.5 mm in diameter; spores 6μ × 8μ.

CHEMISTRY.—Cortex K+ yellow, medulla K−, C−, KC− or KC+ reddish, P+ orange (atranorin and protocetraric acid).

DISTRIBUTION.—Venezuela and Brazil.

HABITAT.—On exposed rocks in open areas and in the paramo at 1500–3500 m elevation.