Flora of New Zealand Series

Lectotype: New Zealand. Sine loco [probably Wellington], C. Knight s.n. – G [fide Archer & Elix (1994a: 210)].

Description : Thallus chalky white, subareolate, surface smooth and dull, without isidia or soredia. Apothecia in pore-like verrucae, concolorous with thallus, conspicuous, numerous, sometimes confluent, flattened-hemispherical, sometimes constricted at base, 1–2 mm diam.; ostioles inconspicuous, pale, translucent, 2–4 per verruca. Ascospores 8 per ascus, uniseriate, ellipsoidal, smooth, 50–62 × 23–28 μm.

Chemistry : TLC−, all reactions negative.

N: Wellington (type collection). S: Otago (Lake Howden). On Hoheria.

Endemic

Illustration : Malcolm & Galloway (1997: 102).

Pertusaria albissima is characterised by: the corticolous habit; the pale, translucent ostioles, the uniseriate arrangement of ascospores in the ascus, and an absence of secondary chemistry. P. leucodes C.Knight (syn. P. cretacea Müll.Arg.) is similar but is distinguished from P. albissima by the black ostioles and the biseriate ascospores (Archer & Elix 1994a: 210).