Pertusaria knightiana
=Pertusaria ceuthocarpa * crenulata Stirt., Proc. phil. Soc. Glasgow 10: 296 (1877).
=Pertusaria whinrayii A.W.Archer, Mycotaxon 45: 423 (1992).
Holotype: New Zealand. Sine loco [probably Wellington], 1883, Dr Knight – G 638/2.
Pertusaria ceuthocarpa *crenulata. Lectotype: New Zealand. Near Wellington, J. Buchanan rec'd 13.ix.1876 – BM [fide Galloway (1985a: 380)].
Description : Thallus fawn to pale-brown, thick, areolate, surface smooth and dull, without isidia or soredia. Apothecia verruciform, sparse, usually confluent, subhemispherical to flattened-hemispherical, concolorous with thallus, constricted at base, 0.8–2 mm diam.; ostioles black, conspicuous, noticeably sunken, 0.1–0.15 mm diam., 1–2 per verruca. Ascospores 2 per ascus, ellipsoidal, rough, 140–200 × 40–50 μm.
Chemistry : K+ yellow→red, KC−, C−, Pd+ yellow; containing 4,5-dichlorolichexanthone (major-minor), norstictic acid (major) and connorstictic acid (tr.) (Archer 1997: 164; 1999a: 4).
N: Wellington. Still very poorly known and collected in New Zealand. Known only from type collections. Known also from Tasmania (McCarthy 2003c, 2006; Archer 2004a).
Australasian
Illustration : Flora of Australia 54 (1992: 419, fig. 6).
Pertusaria knightiana is characterised by: the saxicolous habit; asci with 2 rough ascospores; and the presence of norstictic acid and 4,5-dichlorolichexanthone. It is distinguished from the superficially similar P. subverrucosa by the chemistry and spores – P. subverrucosa has smooth ascospores and lacks 4,5-dichlorolichexanthone.
