Tephromela atroviolacea (Flot. in Nyl.) Fryday comb. nov.
MycoBank No.: MB519205
Basionym: Lecanora atroviolacea Flot., in Nyl. Lich. Fueg. et Patag. 21–22 (1888)—Aspicilia atroviolacea (Flot.) Hue, Nouv. Archiv. du Muséum, ser. 5.2: 530 (1912); type: Falkland Islands, [orient. sinum Port William] super saxa quartoza in Ins. Maclovianis, [Sept.] 1850, Lechler, (Plantae Insularum Maclovianae #60: lectotypus—B (4421)!, hic designatus; isolectotypi—B (4420)!, M!, H-Nyl!, S).
Aspicilia orbiculata Darb., Wiss. Ergebn. Schwed. Südpolar-Exped. 4(11): 11 (1912); type: Falkland Islands, Port Louis, 1902, C. Skottsberg (holotypus—S!).
Description
Thallus creamy yellow to orange, thick, (1–1·5 mm), 2–5 cm across, delimited and ± slightly effigurate at margin, sometimes with a thin blue-black prothallus; areolate, areoles 0·5–2·0 mm across, flat to slightly convex; cortex lacking but surface cells with pale brown pigment. Photobiont chlorococcoid, 9–15(–17) µm diam.
Apothecia black, cryptolecanorine, innate, orbicular, 0·6–0·8 mm diam., 1–2(–3)/ areole; disc black, concave to flat; thalline margin 0·05 mm wide, concolorous with, and often indistinguishable from, the thallus but sometimes separated from it by a narrow crack. Hymenium 170–200 µm tall, purple (at least in streaks); subhymenium more densely pigmented; epihymenium purple; paraphyses septate, sparingly branched and anastomosing, with a gelatinous sheath, 3 µm thick widening to 5–8 µm at the apex with a pigmented cap. Hypothecium golden brown, 25–35 µm tall, with a narrow hyaline zone (c. 20 µm) above. Ascus Bacidia-type, 70– 80 × 15–18 µm, cylindrical; ascospores simple, hyaline, thick-walled, 13–15 × 8–10 µm. Proper exciple thin, 15–20 µm, of radiating hyaline hyphae. Thalline exciple containing angular crystals not dissolving in K; cortex lacking.
Conidiomata pycnidia, often present, sometime abundant, black, round to slightly elongate (c. 0·05 mm diam.), immersed in the thallus; conidia straight, c. 10 × 0·8 µm.
Notes. Tephromela atroviolacea is an easily recognized species with its yellow-orange thallus and large, innate apothecia. Tephromela lirellina is similar but generally has a paler thallus and elongate apothecia. The two species are readily separated microscopically by the blue-black (H+ bright blue, N+ red; cinereorufa-green) epihymenium of T. lirellina. Tephromela atroviolacea appears to be frequent on the Falkland Islands and Isla de los Estados, but is apparently almost absent from the rest of southern South America being known only from a single collection from the extreme eastern tip of Isla Grande de Tierra del Fuego. It is also known from Îles Kerguelen.