Diploschistes gypsaceus
≡Urceolaria gypsacea Ach., Lichenogr. universalis: 338 (1810).
Description : Thallus crustose, uniform, cracked to areolate, areolae 0.8–2 mm diam. Upper surface matt, grey to chalky white, densely pruinose. Apothecia urceolate, 2–5 mm diam. Proper exciple blackish, to 65 μm thick. Hymenium 120–190 μm tall, colourless. Asci subclavate to cylindrical, 90–130 × 20–30 μm, 4-spored. Ascospores brown, muriform, broadly ellipsoidal, 25–40 × 10–17 μm, 4–7 transverse septa, 1–2 longitudinal septa per transverse segment. Pycnidia not seen.
Chemistry : K−, C+ red, Pd−, UV−; containing lecanoric acid.
N: Wellington (NW Ruahine Ra.). S: Nelson (Mt Owen Ra.). On limestone and marble, Widespread in Mediterranean climates on calcareous rocks in somewhat shaded and damp sites. Known also from Iceland, Great Britain, Europe, the Azores, Scandinavia, North and South America (Colombia, Venezuela), India and Nepal, and Australia (Lumbsch 1989; Pant & Upreti 1993; Lumbsch & Elix 2003; McCarthy 2003c, 2006).
Cosmopolitan
Illustrations : Lumbsch (1989: 170, fig. 22B–D); Pant & Upreti (1993: 40, fig. 4D).
Diploschistes gypsaceus is characterised by: the saxicolous habit (basicolous rocks); a whitish, pruinose thallus; uniseriate, 4-spored asci; brown muriform ascospores, 25–40 × 10–17 μm; and lecanoric acid in the medulla.
