Flora of New Zealand Series

≡Lichen ocellatus Vill., Hist. Plant. Dauph.: 988 (1789).

=Diploschistes sanguinescens Zahlbr., Denkschr. Akad. Wiss. Wien math.-naturwiss Kl. 104: 265 (1941).

Diploschistes sanguinescens. Isotype: New Zealand. Otago Heads, on rock, J.S. Thomson T 1017 [ZA 38] – OTA 029326.

Description : Thallus crustose, uniform, thick, areolate cracked, areolae 0.4–2.5 mm diam. Upper surface covex to bullate, greyish to whitish, pruinose. Apothecia lecanorine, rounded to 3 mm diam., disc blackish, finely white-pruinose. Proper exciple to 80 μm thick. Hymenium 100–150 μm tall. Asci cylindrical, 95–140 × 15–25 μm, 8-spored. Ascospores broadly ellipsoidal, colourless to brownish, muriform, 20–37 × 7–15 μm, with 3–6 transverse septa and 1–3 longitudinal septa per transverse segment. Pycnidia immersed, cerebriform. Conidia bacillar, 4–7 × 1–1.5 μm.

Chemistry : K+ yellow→red, C−, Pd+ orange, UV−; containing stictic and norstictic acids.

N: South Auckland (Carter's Beach near Raglan). S: Otago (Otago Harbour). On coastal rocks. Known also from Europe, Macaronesia, Cape Verde Is, Morocco, Algeria, Libya, Somalia, Namibia, Turkey, the Caucasus, Saudi Arabia, Oman, Israel, China and Australia (Lettau 1937; Lumbsch 1989; Lumbsch & Elix 2003; McCarthy 2003c, 2006; Nimis & Martellos 2003) on calcareous substrata. Still very poorly collected in New Zealand.

Cosmopolitan

Illustrations : Lettau (1937: tab. 4, fig. 53); Lumbsch (1989: 137, fig. 1C; 139, fig. 4B; 144, fig. 7; 178, fig. 27A–C); Guderley & Lumbsch (1996: 289, fig. 13A).

Diploschistes ocellatus is characterised by: the saxicolous habit; the thick, verrucose, white-pruinose thalli and the distinctive chemistry. D. ocellatus differs from all other species in the genus in having lecanoroid ascomata, the presence of norstictic acid, and the absence of a pseudoparenchymatous true excipulum with lateral paraphyses. These differences in ascomatal anatomy were interpreted as reductions in connection with the lecanoroid apothecia in that species (Guderley et al. 1997). Cladistic analysis of Diploschistes suggests that D. ocellatus is a derived member of the scruposus group (Lumbsch & Tehler 1998). A recent molecular study (Martín et al. 2003) has D. ocellatus as a sister group to Diploschistes s. str., suggesting that D. ocellatus is a distant basal member of Diploschistes, or that it may even represent a distinct lineage within the Thelotremataceae.