Pertusaria hypoxantha
Description : Thallus dull- to bright-yellow, areolate, surface smooth and dull, without isidia or soredia. Apothecia verruciform, uncommon, scattered, rarely confluent, concolorous with thallus, slightly flattened-hemispherical, becoming constricted at base, 0.6–1 mm diam.; ostioles inconspicuous, pale to dark yellow-brown, 1 per verruca. Ascospores 8 per ascus, irregularly uniseriate, ellipsoidal, rarely subfusiform, smooth, 55–75(–90) × 25–35 μm.
Chemistry : K−, KC+ orange, C+ orange, Pd− or + weak-yellow; containing thinophaninic acid (major), 2-chloro-6- O -methylnorlichexanthone (tr.), stictic acid (major), constictic acid (minor), and ±lichexanthone (minor-tr.) (Archer 1997: 79).
N: Northland (Hen I., Little Barrier I.) on coastal rocks. Also in E Australia (Queensland, New South Wales) and Brazil (Malme 1936; Archer 1997, 2004a; McCarthy 2003c, 2006).
?Pantropical
Illustration : Archer (1997: 163, fig. 65).
Pertusaria hypoxantha is characterised by: the saxicolous (coastal rocks) habit; the yellow thallus without isidia or soredia; 8-spored asci; and the presence of thiophaninic and stictic acids. It is distinguished from P. xanthoplaca by the absence of soredia.
