MB845154

Distinguished from G. contristans and G. squalescens by the lack of a visible thallus and from G. holomeloides by the longer ascospores. Further distinguished from all three species by its DNA sequence data.

Type: Falkland Islands, West Falkland, Port Howard, Mt Maria, Lightning Rocks, 51.619028°S, 59.601849°W, 575 m, over bryophytes on S-facing rocks, 26 January 2015, A.M. Fryday 10914 (holotype: MSC; isotype: E).

Description:

Thallus effuse, covering several cm2, at most a thin, pale brown gelatinous film may be present; apothecia arising directly from the Gymnomitrion substrate. Photobiont chlorococcoid, a few cells c. 10–15 μm diam. with a thick hyaline wall 1–2 μm wide, but not definitely associated with the fungus.

Apothecia black, lecideine, strongly convex even when immature, proper margin not apparent, 0.2–0.5 mm diam; usually ± orbicular but larger apothecia becoming irregular or even slightly lobed. In section, proper exciple not apparent. Hymenium 50–70 μm tall; paraphyses 1.5–2(–2.5) μm wide, septate, cells 15–20(–25) μm long, not constricted at the septum, slightly branched especially towards the apices, which are not swollen and are immersed in a hymenial gel; upper 5– 10 μm (epihymenium) patchily dark blue- (K+ greenish-blue, N+ magenta), overlayed by a few minute granules that are POL–, K–, N+ blue, lower 30–70 μm dilute grey (K+ dilute purple-brown, N+ orange-red) with dark streaks and spots (K+ blue-black, N+ magenta); lower part (subhymenium) merging imperceptibly into the hypothecium. Hypothecium massively developed (−350 μm deep), composed of randomly organized, hyaline hyphae, c. 3 μm wide with numerous dark blue streaks and spots (K+ greenish-blue, N+ magenta). All pigments ultimately N+ magenta. Asci Biatora-type, cylindrical c. 30 × 10 μm, becoming clavate and c. 15 μm wide; ascospores hyaline, 1-septate, (14–)15.4 ± 0.9(–17) × (3–)3.3 ± 0.3(–4) μm; l/b ratio (4.3–)4.7 ± 0.3(–5.1), n = 20, narrow ellipsoid with rounded, pointed attenuated apices, but with one end more rounded and the other tapering to a more pointed apex. Conidiomata not observed.

Chemistry: All spot tests negative. No substances detected by tlc.

Etymology: The epithet is derived from Astrape (ἀστραπή), the Greek goddess of lightning and the type locality ‘Lightning Rocks’.

Ecology and distribution: Known only from the type collection, which occurred on a bryophyte (Gymnomitrion sp.) mat on a siliceous rock outcrop in wind-swept, alpine tundra. Associated species: Coccotrema corallinum Messuti and Lepra argentea Fryday.