Flora of New Zealand Series

≡Arthonia pellucida C.Knight, Trans. N. Z. Inst. 15: 352 (1883).

Holotype: New Zealand. Sine loco [probably Wellington], 22.xi.77, Charles Knight – WELT – Herb Knight Vol. 63A, p. 9. This material has drawings of asci, ascospores and a section of the apothecium made by Knight, and used for the engravings illustrating the type description. Knight material from the BM was earlier chosen as lectotype [fide Galloway (1985a: 19)], but this must now properly be regarded as isotype.

Description : Flora (1985: 19).

N: ?Wellington. Known only from the type collection.

Endemic

Illustration : Knight (1883: pl. XXXV, fig. 4b)

Arthothelium pellucidum is characterised by: the corticolous habit; the thin, arachnoid, grey-white rather eroded thallus not delimited by a black, prothalline line; reddish brown to black, depressed-innate, rounded to effigurate or branched apothecia, 0.2–1.1 mm diam.; epithecium brown; hymenium hyaline, 3–50 μm tall; hypothecium hyaline; asci bitunicate, pyriform, pedicellate, 3–45 × 30–40 μm; and cuneate-oblong, brownish ascospores, with an enlarged terminal cell and a muriform tail, (20–)22–25 × 8–10 μm.