Wirthiotrema glaucopallens (Nyl.) Rivas Plata, Kalb & Frisch

Thelotrema glaucopallens

Thelotrema glaucopallens Nylander, 1863:327.

Pyrenula clandestina Acharius, 1814:10 [type-collection: on Cinchona flava, South America (H, lectotype; S, isotype)].

Thelotrema laevigans Nylander var. avertens Nylander, 1867:318 [type-collection: Tequendama, Colombia, Lindig 893 (H, lectotype; BM, FH-Tuck, G, P, W, isotypes)].

Thelotrema pechueli Müller-Argau, 1880:34 [type-collection: Quillu River, Angola, Pechuel-Loesche s.n. (G, lectotype); Figure 16e].

Ocellularia clandestina (Acharius) Müller-Argau, 1877a:7.

Thelotrema homopastoides Vainio, 1896:207 [type-collection: Richmond Valley, St. Vincent, Elliott 327 (TUR, lectotype; BM, isotype); Figure 16g].

Thelotrema butuanum Vainio, 1921:183 [type-collection: Luzon, Philippines, Fenix, BS-28347 (W, lectotype); Figure 16f].

TYPE-COLLECTION.—Cuba, Wright (FH-Tuck, lectotype, as 28; L, UPS, isotypes) (Figure 16d).

Thallus light greenish gray, very thin and shiny, breaking away in thin sheets, forming extensive colonies up to 15 cm broad; apothecia numerous to rather rare, immersed to slightly emergent, 0.2–0.4 mm in diameter, uncarbonized or slightly carbonized apically, without a columella; pore flush to barely raised, round, rarely angular, 0.05–0.12 mm in diameter; hymenium 60μ–80μ high; spores 8/ascus, muriform, 6–8 loculate transversely, 2–3 loculate longitudinally, 7μ–10μ × 15μ–24μ, I– (Figure 16h).

CHEMISTRY.—Stictic and constictic acids.

HABITAT.—Buttresses, base of large trees, exposed roots, lianas, rarely upper bole and canopy in the rain forest (450–800 m).

The thallus of this pantropical species is unique. It is extremely thin and shiny and tends to break away in thin waxy sheets when bruised or cut. The color is a pyrenocarplike dark yellowish green. Apothecia are usually quite numerous with flush pores having considerable variation in development of a rim, from no distinct annulus to an obviously raised area. Some anomalous specimens may even have semi-emergent apothecia, but the small I– spores and the presence of stictic acid will positively identify them.

SPECIMENS EXAMINED.—10 (38082), 11 (37999, 38008, 38047), 15 (35147), 16a (37670, 37876, 38043, 38044), 20a (37783), 21 (38083, 38095, 38155, 38156), 23 (37678), 26b (35367), 27 (37891), 28 (35431).