Flora of New Zealand Series

=Thelotrema bicavatum Nyl., Flora 47: 269 (1864).

≡Ocellularia bicavata (Nyl.) Müll.Arg., Bull. Herb. Boissier 2, App. 1: 74 (1894).

Thelotrema bicavatum. Holotype. New Zealand. Sine loco [probably Auckland], Hochstetter – H-NYL 22790.

Description : Thallus pale ochraceous, matt, 10–80 μm thick. Cortex amorphous, 5–15 μm thick. Apothecia scattered, subspherical, flush with substratum or slightly raised from it, 0.4–0.7 mm diam., openings to 0.4 mm diam., thalline exciple incurved. Exciple colourless, detached, c. 25 μm thick. Periphyses 5–8 μm long. Hymenium 90–110 μm tall. Ascospores 4–8 per ascus, 2–3-seriate, colourless, oblong-fusiform, transversely septate (8–14 locules), I+ purple, 30–45 (–54) × 7–9 μm.

Chemistry : TLC−, all reactions negative.

N: ?Auckland. Known also from Great Britain, Scandinavia, North America, India, Japan, Java, Philippines, Hawai'i, and New Caledonia (Salisbury 1972a; Hawksworth 1992c; Santesson 1993; Esslinger & Egan 1995; Elix & McCarthy 1998; Matsumoto 2000; Brodo et al. 2001).

Cosmopolitan

Illustrations : Salisbury (1972a: 264, fig. 1); Purvis et al. (1995: 355, fig. 6C); Matsumoto (2000: 42, fig. 18E, F; 19, fig. 19).

Thelotrema subtile is characterised by: the corticolous habit; the pale-ochraceous or whitish grey thallus; flush to slightly raised apothecia; small, colourless, transversely septate ascospores; and a negative thallus chemistry.