Hypotrachyna protenta Hale

Hypotrachyna protenta

Thallus laxe adnatus, saxicola, 6–10 cm diametro, lobis sublinearibus, imbricatis, 2–4 mm latis; cortex superior 14μ–16μ crassus, stratum gonidiale 24μ crassum, medulla alba, 80μ–90μ crassa, rare pro parte aurantiaca, cortex inferior 14μ–16μ crassus; subtus niger, modice rhizinosus. Apothecia numerosa, substipitata, sporis simplicibus, 6μ × 12μ.

Thallus rather loosely adnate on rocks, the colonies easily breaking apart, whitish ashy, 6–10 cm broad; lobes sublinear, more or less crowded or imbricate, variable, 2–4 mm wide, sometimes becoming densely appressed lobulate toward older parts; upper surface shiny, plane to minutely rugulose, often heavily pycnidiate, soredia and isidia lacking; lower surface densely rhizinate, the rhizines sparsely to moderately dichotomously branched, sometimes projecting as a narrow mat along the margins. Apothecia numerous, adnate, 4–8 mm in diameter; spores 6μ × 12μ.

CHEMISTRY.—Cortex K+ yellow, medulla K−, C−, KC+ red, P− (atranorin, alectoronic acid, α-collatolic acid, and, if pigmented, rhodophyscin).

TYPE COLLECTION.—Open forest along stream, on rocks, El Valle, Mérida, Venezuela, Hale 43365, February 1974 (US, holotype; DUKE, TNS, UPS, isotypes).

DISTRIBUTION.—Central America, Colombia, and Venezuela southward to Peru, and Brazil.

HABITAT.—On rocks in open forests and in the paramo at 1700–4000 m elevation.