Tephromelae atrae similis sed apotheciis usque ad 5 mm diam., excipulo thallino ± excluso, thallo laevi tenui minus quam 0·5 mm crasso, hypothecio supero hyalino 50–80 µm elato.
Typus: Argentina, Tierra del Fuego Province, Isla de los Estados, Puerto Roca, summit of peak S of bay, 21 October 1971, H. A. Imshaug (51113) & K. E. Ohlsson (MSC—holotypus).
Description
Thallus creamy white, sometimes with a slightly yellowish or pinkish tinge, thin to 0·5 mm thick, widespreading with a thin, blackish prothallus; cracked-areolate, areoles flat, smooth, 0·5–1·2 mmacross; cortex lacking, medulla with minute inclusions not all dissolving in K. Photobiont chlorococcoid, (9–)12–15 µm diam.
Apothecia adnate when young becoming slightly sessile when mature, blue-black, orbicular 1·2–5·0 mm diam., disc slightly convex to almost hemispherical, often irregularly cracked; separated from the thallus by a narrow crack with part of thallus attached to the apothecium and forming a thalline margin; thalline margin thin, partially developed when young becoming excluded in mature apothecia. Hymenium 120–150(–250) µm tall; paraphyses septate, not branched and anastomosing, with a gelatinous sheath, c. 3 µm thick, not or only slightly swollen at the apex to 3–5 µm; epihymenium purple (atra-red). Hypothecium golden brown below, lower cells vertically orientated and forming a ‘root’ into the thallus, 200 µm tall, upper layer hyaline sometimes with blue-black pigment (H+ blue, N+ red cinereorufagreen), 50–80 µm tall. AsciBacidia-type, 65–75 × 18–20 µm, ± clavate; ascospores simple, hyaline, thin-walled, 12–13 × 8– 10 µm. Proper exciple not well-developed. Conidiomata not observed.
Chemistry. Atranorin, α-collatolic acid, ±alectoronic acid, ?physodic acid by TLC.
Notes.Tephromela superba is characterized by its massive apothecia (up to 5 mm diam.), thin thallus (up to 0·5 mm), relatively low hymenium (< 250 µm, usually less than 150 µm), unbranched paraphyses that are not swollen at the apex, and a wide, hyaline upper hypothecium c. 70 µm wide and a massively developed lower, golden brown hypothecium (to 200 µm). The hyaline band in the upper hypothecium is also present in most other species of the group (e.g., T. atroviolacea (Flot.) Fryday) but is rarely more than 20 µm wide. The greater width of this band is not a consequence of the massive apothecia of T. superba because it is also present in relatively small apothecia of this species.