Flora of New Zealand Series

Holotype: New Zealand. Otago, Otago Peninsula, Papanui Inlet, N side, on rocks – part of old causeway – along edge of estuary/salt marsh, 1 m, 1.i.1996, P.N. Johnson 1908 – CHR 523671.

Description : Thallus thin, closely attached, in discrete to coalescing rosettes, (0.3–)0.5–1.5(–2) cm diam, often spreading more widely in patches to 6 cm diam, with a well-developed marginal, fibrous, arachnoid pale prothallus. Upper surface pale creamish or fawnish, to greensih white in irregular spots or patches, areolate, areolae angular, minute, 0.1–0.4 mm diam., separated by deep cracks, occasionally surface is continuous and then minutely papillate-irregular (×10 lens), K−. Apothecia minute, solitary and widely scattered to crowded and ±central, sessile, rounded to rarely contorted through mutual pressure, 0.1–0.6(–0.8) mm diam., disc golden yellow to yellow, matt or slightly glossy, plane to subconvex, thalline margin rarely present as small granules around apothecia, concolorous with thallus; proper margin persistent, entire, slightly raised, glossy, smooth, paler than disc. Epithecium yellow, densely granular, 8–12 μm thick. Hymenium colourless, without oil droplets, 45–60 μm tall. Paraphyses slender, 2 μm thick, apical cells swollen, submoniliform, occasionally furcate, 5 μm diam. Asci cylindrical to clavate, 40–55 × 10–13.5 μm, 8-spored. Ascospores biseriate in ascus, narrowly ellipsoidal, apices rounded or slightly pointed at one end, 10–12(–15) × 5–6.5 μm; septum very thin, 1.5–2 μm thick.

Chemistry : Thallus K−; apothecia K+ reddish purple containing parietin.

N: Wellington (Wellington Airport coast). S: Otago. On coastal rocks in high-tide zone, often overgrowing Verrucaria maura and intermixed with other species of Caloplaca and Xanthoria ligulata.

Endemic

Illustration : Galloway (2004c: 107, fig. 3).

Caloplaca papanui is characterised by: the saxicolous habit (coastal rocks); the pale creamish or greenish white, arachnoid to minutely areolate thallus, or a complete absence of thallus; minute, scattered to clustered, golden yellow to yellow apothecia; and the narrowly ellipsoidal ascospores with only a very thin septum, in some cases the spores appearing 1-septate and almost not polarilocular. The ascospores of C. papanui are similar in structure to those of C. approximata (Lynge) H.Magn. (Magnusson 1946: 130), an alpine, circumpolar species from overhanging rocks in Scandinavia, the Arctic, North America and the Scottish Highlands (Magnusson 1946; Laundon 1992; Brodo et al. 2001; Gilbert 2001), but in this species the apothecia are bright orange, and the thallus is very poorly developed.