Flora of New Zealand Series

=Caloplaca acarocarpa Zahlbr., Denkschr. Akad. Wiss. Wien math.-natuwiss Kl. 104: 368 (1941).

Lectotype: New Zealand. Rangitoto I., on coastal rock, H.H. Allan Z96 – CHR 373787 [fide Galloway (1985a: 62)].

Caloplaca acarocarpa. Lectotype: New Zealand. Rangitoto I., on coastal rock, H.H. Allan 52 – CHR 373658 [fide Galloway (1985a: 62)].

Description : Thallus of widely scattered, minute, whitish to orange granules, 1.0 × 0.2 mm, suberect or convex, unevenly swollen, effuse or lacking, K+ reddish purple. Apothecia scattered, sessile, solitary to clustered in small groups, rounded or contorted through mutual pressure, 0.1–0.5 (rarely to 1) mm diam., disc urceolate at first becoming plane, orange, matt; thalline margin restricted to a thin, pale collar around disc, concolorous with thallus; proper margin prominent, persistent, swollen, obscuring disc at first, pale orange-yellow, paler than disc. Epithecium yellow, densely granular 8–15 μm thick. Hymenium colourless, without oil droplets, 60–75 μm tall. Paraphyses slender, 1.5–2 μm thick, apical cells submoniliform, 4–5 μm diam. Asci cylindrical, 50–65 × 12–15 μm, 8-spored. Ascospores broadly ellipsoidal to ovoid, (10–)11.5–13 × (5–)6–8.5 μm; septum 5–7 μm thick, ½ the length of the spore.

Chemistry : Thallus K+ purple; containing emodin, parietin, fallacinol, fallacinal, xanthorin and erythroglaucin (Santesson 1970: 2151).

N: Northland (Hen I. to Rangitoto I.). Known only from northern coastal rocks. Common on volcanic rocks, the many interstices offering suitable niches for the widely scattered, granular thallus.

Endemic

Caloplaca acheila is characterised by: the saxicolous habit (coastal rocks); the minute, scattered granular thallus; minute apothecia; and broadly ellipsoidal to ovoid ascospores, 10–13 × 5–8.5 μm with a thick septum to ½ the length of the spore.