Pertusaria gymnospora
Description : Thallus whitish grey to pale-grey, thick, lumpy and warty, papillate, without a prothallus, spreading over substratum (mosses, bark, detritus) to 20 cm diam. Papillae to 3 mm tall, 0.8–1.2 mm diam., ±cylindrical, constricted slightly at base, simple or occasionally bifurcate, rarely 2–3-confluent; surface verrucose and fissured; apices expanded, ±subglobose, becoming cracked, exfoliating and excavate. Apothecia immersed at tips of papillae, 1–4 per papilla, 0.8–1 mm diam., ±hemispherical, covered by a thin, greyish to pinkish thalline veil. Paraphyses 0.5–1.5 μm thick, densely reticulate, apices swollen to 2.5 μm. Asci clavate, 195–220 × 80–150 μm, walls 7–14 μm thick. Ascospores 1 per ascus, colourless, broadly ellipsoidal to ±globose, 85–180 × 50–150 μm, guttulate, with a gelatinous sheath not dissolving in K, discharge through ruptured. eroding apices of fertile papillae, pale-orange to ±translucent, visible (×10 lens) scattered on surface of thallus and papillae; wall single 2–15(–22) μm thick, internally rough and sculptured when mature, easily broken.
Chemistry : K−, KC−, C−, Pd+ red; containing protocetraric acid.
N: South Auckland (Coromandel Peninsula, Pakirarahi, Waimiha). S: Westland (Denniston Plateau, Kelly Ra.), Canterbury (Temple Basin, Arthur's Pass), Otago (Central Otago mountains, Lammerlaw Ra., Rock & Pillar Ra. etc.); Southland (Fiordland, Deadwood Lagoon below Henry Saddle). St: (Mt Anglem, Fraser Peaks). Overgrowing mosses and plant detritus on ground, or on bark of trees (e.g. Dacrydium cupressinum), alpine to subalpine. Also in SW Tasmania (Kantvilas 1990b; Archer 1997, 2004a; McCarthy 2003c, 2006).
Australasian
Illustrations : Kantvilas (1990b: 291, fig. 1B; 294, fig. 2A, B; 295, fig. 3B).
Pertusaria gymnospora is characterised by: the corticolous/muscicolous habit; the thick, whitish lumpy thallus encrusting the substratum, usually leaving details such as bryophyte leaves etc. evident below; the well-developed papillate isidia with apothecia terminal on the papillae; and the presence of protocetraric acid. It resembles P. dactylina; however, this species has more slender, regularly cylindrical and smooth-walled papillae, that are often very numerous and crowded, appearing caespitose.
