Flora of New Zealand Series

Holotype: New Zealand. Northland, 4–5 km NNE of Orewa, Waiwera Hill Scenic Reserve, on trunk of old Metrosideros excelsa, 36º33's, 174º43'E, 60 m, 5.xi.1986, L. Tibell 16693 – UPS. Isotype – UPS.

Description : Thallus epiphloeodal, sulphur-yellow, continuous or cracked, when well-developed wrinkled or granular, to 500 μm thick. Apothecia rounded to irregular, 0.3–2 mm diam., numerous, scattered singly or in groups of 2–3 and then deformed through mutual pressure, sessile, constricted at base, covered with a whitish, greyish or yellowish pruina. Margin at first thick, elevated above disc, persistent, at maturity and then rather thin. Disc plane to subconvex. Hymenium 90–120 μm tall, I+ blue. Hypothecium 35–50 μm thick, clear-brown. Paraphysoids, branched and somewhat anastomosing, 1–1.5 μm thick, their apices swollen and covered with a granular, brown cap. Asci cylindrical–clavate, 75–100 × 14–15 μm. Ascospores fusiform, with one of the apices attenuated, straight, 3-septate, 27–40(–45) × (3.5–)4–5 μm. Pycnidia immersed to semi-immersed, solitary or aggregated in groups, ±rounded, the ostiole wide, occasionally covered with a thin yellowish pruina, subglobose to pyriform, 600 μm tall and 550 μm wide, the wall obscure brownish above, paler below. Microconidia 9–13 × 1–1.5 μm, somewhat curved. Macroconidia 12–20 × 2–3 μm, straight or slightly curved.

Chemistry : Thallus K− or K+ yellow-orange, C− or C+ yellowish, KC−, Pd−; containing schizopeltic acid.

N: Northland (Orewa), Auckland (Waitakere Ra.). On bark of trees (Metrosideros excelsa) in coastal forest.

Endemic

Illustrations : Egea & Torrente (1994: 111, pl. 9F–I).

Lecanactis tibelliana is characterised by: the corticolous habit; the sulphur-yellow thallus; grey- to yellow-pruinose apothecial discs; 3-septate, fusiform ascospores, 27–43 × 3.5–5 μm; and schizopeltic acid in the medulla.