Hypotrachyna physcioides (Nyl.) Hale

Hypotrachyna physcioides

Parmelia physcioides Nylander, 1860:385. [Type collection: Silla de Caracas, Venezuela, Humboldt and Bonpland (P, lectotype; BM, H, isolectotypes).]

Parmelia laevigata var. gracilis Müller Argau, 1879:169. [Type collection: Bogotá, Colombia, André 923 bis (G, lectotype; BM, US, isolectotypes).]

Parmelia boliviana Nylander, 1885:612. [Type collection: Prov. Larecaja and Caupolicán, Bolivia, Weddell (P, lectotype).]

Parmelia gracilis (Müller Argau) Vainio, 1890:55.

Parmelia digitata Lynge, 1914:98. [Type collection: Santa Anna da Chapada, Mato Grosso, Brazil, Malme 2545 (S, lectotype; LD, US, W, isolectotypes).]

Parmelia confusula Zahlbruckner, 1929:162. [Type collection: Based on P. gracilis (Müller Argau) Vainio, not P. gracilis Sprengel, 1827:277, or P. gracilis Müller Argau, 1887:317).]

Thallus adnate to loosely attached, usually rather coriaceous, 6–15 cm broad, ashy white to tannish mineral gray; lobes sublinear, separate to crowded, 2–6 mm wide; upper surface plane to convex, dull and sometimes white pruinose at the tips to shiny and distinctly white-maculate, rarely becoming sparsely to densely lobulate-laciniate toward the center, isidia and soredia lacking; lower surface densely rhizinate, the rhizines densely dichotomously branched. Apothecia adnate to substipitate, 2–10 mm in diameter; spores 6μ–9μ × 12μ–16μ.

CHEMISTRY.—Cortex K+ yellow, medulla K−, C− or C+ orange, KC+ orange, P− (atranorin, barbatic acid, 4-O-demethylbarbatic acid, obtusatic acid, and norobtusatic acid).

DISTRIBUTION.—Mexico, Central America, West Indies, Colombia, Venezuela, Peru, Ecuador, Bolivia, Brazil, and Southeast Asia.

HABITAT.—On trees (conifers and hardwoods) and rocks in open or disturbed forests at 1500–4100 m elevation.