Flora of New Zealand Series

Holotype: New Zealand. South I., Southland, Secretary I., Fiordland, first peak, 909 m, on shaded rock, very rare, ii.1959, J. Murray 4128 – OTA 057852; BM 8251 – isotype.

Description : Thallus rosette-forming to irregularly spreading, or in coalescing patches, closely attached to substratum, 400–650(–800) μm thick, tartareous, (1–)2–5(–7) cm diam., without a marginal prothallus, but with a dark-brown to black prothalline zone underlying thallus and attaching to substratum, 150–250 μm thick, overlain by a pigmented, ochraceous zone, 50–100 (–250) μm thick, the pigment commonly visible as an ochraceous zone at base of cracks near centre of thallus, and reacting K+ reddish purple. Upper surface pale-pinkish or pinkish white when dry (pale lettuce-green when wet); uniform, smooth or shallowly undulate, minutely maculate through regular discontinuities in photobiont layer, small, isolated clumps of photobiont appearing as minute, green maculae (×10 lens) when wet; without isidia, pseudocyphellae or pruina; dissected by long, deep, parallel cracks radiating from centre to margins, cracks dividing margins into contiguous, flabellate lobes (1–)2–4(–6) mm wide. Margins entire, flat or shallowly convex, suffused brownish, abruptly and neatly delimited. Medulla white, with an ochraceous pigment (K+ reddish purple) in lower parts. Photobiont green, chlorococcoid, in dense clusters, cells rounded, 5–7 μm diam., in a discontinuous layer 140–150 μm thick. Cephalodia immersed, level with thallus surface, elongated, vein-like, never rosette-forming, 1–3 mm wide, 1–3 cm long, dividing into 2–3 branches towards periphery, radiating centrally and penetrating thallus to within 1 cm of margins, puplish blue when moist, pale pinkish white when dry, surface smooth or cracked, not pruinose; cyanobiont Scytonema, in chains, cells compressed, cylindrical to fabiform, 10–12.5 μm diam. Apothecia immersed, aspicilioid, developed on central areolae and delimited by narrow to deep cracks, solitary to 2–4-together, round to irregular or deformed through mutual pressure, 0.5–1.5(–2.5) mm diam., disc concave to plane, red-brown, covered with a thin to thick, pinkish or pale-brownish pruina. Thalline margin prominent, entire, smooth to minutely papillate, swollen, 0.2 mm thick, pale-pinkish. Proper margin very thin, visible as a pale-pinkish rim to disc, often separated from thalline margin by a narrow crack. Epithecium brownish, granular, 15–30 μm thick. Hymenium hyaline to pale yellowish brown, 150–200(–225) μm tall. Hypothecium opaque, densely interwoven, yellow-brown to dark red-brown. Asci cylindrical, 130–150 × (12–)15–20 μm. Ascospores uniseriate in ascus, broadly ellipsoidal to oval, apices rounded or pointed, (20–)23–27(–28.5) × 15–17.5 μm. Pycnidia widely scattered, immersed in thallus, 250–350 μm diam., ostiole punctiform-depressed, pale red-brown. Conidia not seen.

Chemistry : Thallus K− (above), K+ red-purple (lower medulla), C+ red, KC+ red, Pd−; containing gyrophoric acid (major), 5- O -methylhiascic acid (minor), lecanoric acid (minor), and two unidentified anthraquinones (minor) reacting K+ red-purple.

S: Southland (Secretary I., Head of Gorge Burn, S arm of Lake Te Anau, Dusky Sound, Mt Hodges). On hard rocks above treeline in high-rainfall areas both east and west of the Main Divide in Fiordland. Here it associates with Porina guentheri (q.v.), Porpidia macrocarpa (q.v.) and other species of Placopsis, including P. aspicilioides, P. lambii, P. macrophthalma and P. subcribellans, and also with an unidentified, athalline species of Scolicosporum. First collected by James Murray from Secretary I. in 1959 (see Murray 1963a), but still only rarely collected.

Endemic

Illustration : Galloway (2004a: 157, fig. 4).

Placopsis murrayi is characterised by: the thick, tartareous, closely attached thallus with neatly delimited, pleated margins; a white medulla suffused with a yellow pigment (K+ reddish purple) in the lower parts; conspicuous long, deep, parallel cracks radiating from centre to margins; characteristic immersed, elongated, vein-like cephalodia; immersed aspicilioid apothecia developing centrally; and broadly ellipsoidal to ovoid ascospores, (20–)23–27(–28.5) × 15–17.5 μm. It is distinguished from P. macrophthalma (q.v.) by the elongated vein-like cephalodia, and the differing chemistry. The Campbell I. endemic, P. venosa (q.v.), has smaller ascospores, narrower cephalodia, and a different chemistry.