Myriotrema clandestinum (Fée) Hale

Thelotrema clandestinum

Thelotrema clandestinum Fée, 1837:90.

Thelotrema subcaesium Nylander, 1869:120 [type-collection: Brazil, Glaziou 2193 (H, lectotype; BM, C, FH-Tuck, UPS, US, W, isotypes); Figure 14h].

Thelotrema concretum Fée var. subcaesium (Nylander) Redinger, 1936:96.

TYPE-COLLECTION.—On Cinchona lancifolia in America, without collector (G, lectotype). (Figure 14g).

Thallus whitish to greenish ashy gray, shiny, thick, and continuous, forming colonies up to 20 cm broad; apothecia numerous, immersed, 0.15–0.3 mm in diameter, noncarbonized and without a columella; pore flush, round, 0.07–0.1 mm in diameter, usually with a whitish rim; hymenium 65μ–75μ high; spores 8/ascus, uniseriate, 4–5 loculate, muriform with 1–2 longitudinal septae in at least one of the locules, 6μ–10μ × 15μ–20μ, I+ blue (Figure 14i).

CHEMISTRY.—Psoromic and conpsoromic acids.

HABITAT.—Canopy branches in rain forest (500–670 m).

Thelotrema clandestinum has small spores with few longitudinal septations. It would, in fact, be classified as an Ocellularia unless the spores are carefully examined. Chemically similar O. terebratula has only transverse septae. Both species have a thick, continuous thallus and occupy the same kind of habitat. They were collected at a total of ten localities but never together in the same one.

SPECIMENS EXAMINED.—13 (35298, 35393), 14 (35103, 35105, 35136), 15 (35207), 16c (37768, 37872, 37981), 24b (35624a).