Flora of New Zealand Series

Holotype: New Zealand. Chatham Island, just W of Waitangi wharf, Ellice Point, on coastal rock, on ledge of tuff on headland, 3 m, 28.iii.2000, P.N. Johnson 3472 – CHR 523670.

Description : Thallus spreading in irregular, chinky patches, 1–3 cm diam., distinctly areolate, without a noticeable prothallus; areolae angular, 0.5–2 mm diam., separated by deep cracks, surface convex, verruculose-papillate to minutely cerebriform (×10 lens); pale greenish white, distinctly maculate (×10 lens) when wet, grey-white when dry, K−. Apothecia conspicuous, 1–3 per areolae, sessile, rounded to contorted through mutual pressure, (0.2–)0.5–1(–1.5) mm diam., disc plane to convex, matt or glossy, orange when dry, clear-yellow when wet; thalline margin persistent, thin or thick, verrucose-papillate, maculate (×10 lens), concolorous with thallus; proper margin thin, pale-yellow, often obscured. Epithecium yellow, granular, 8.5–13.5 μm thick. Hymenium colourless, inspersed with oil droplets, 60–70 μm tall. Paraphyses slender, 1.5–2 μm thick, apices furcate and swollen, 3.5–5 μm diam. Hypothecium massive, inspersed with oil droplets. Asci clavate, 50–60 × 12–16.5 μm, 8-spored. Ascospores ellipsoidal, apices rounded, (10–)11.5–13.5 × 5–6.5 μm; septum 2–3.2 μm thick, ¼ the length of spore.

Chemistry : Thallus K−, apothecial disc K+ reddish purple; containing parietin.

Ch: Known only from the type locality. Associating with Xanthoria ligulata.

Endemic

Illustration : Galloway (2004c: 107, fig. 1).

Caloplaca maculata is characterised by: the saxicolous habit (coastal rocks); the chinky, white, K−, verruculose-papillate, maculate thallus; conspicuous pale-orange apothecial discs (yellow when wet) with persistent, maculate thalline margin concolorous with thallus; hymenium with inspersed oil droplets; medium-sized ascospores 10–13.5 × 5–6.5 μm, with a rather narrow septum, ¼ the length of the spore.