Flora of New Zealand Series

≡Lecanora xantholyta Nyl., Flora 62: 361 (1879).

≡Leproplaca xantholyta (Nyl.) Hue, Rev. Bot. Courrensan 6: 148 (1887).

Description : Thallus crustose, delimited, entirely leprose-sorediate, orbicular when well developed, but often irregular and scattered, yellow, margins of radiating, plane, pulverulent lobes. Surface thin, usually continuous and ±plane, but rarely of convex granules 0.2 mm diam., rarely areolate, ecorticate, mainly pulverulent. Medulla white, visible where thallus has been rubbed. Apothecia and pycnidia absent. Photobiont green, cells to 18 μm diam.

Chemistry : Thallus K+ violet-red, C−; containing parietin.

S: Nelson (Kaihoka Lakes), Otago (Maungatua). On shaded, vertical, limestone cliffs and on schist rocks (Arup & Mayrhofer 2000: 360) visited by birds – a photophobous, calcicolous and weakly nitrophilous taxon (Laundon 1974). Known also from Great Britain, Europe, Macaronesia, Israel, Turkey, the Ukraine and Tibet (Laundon 1974, 1992; Nimis 1993; Galun & Mukhtar 1996; John 1996; Kondratyuk et al. 1996a, 1996b, 1998; Diederich & Sérusiaux 2000; Scholz 2000; Llimona & Hladun 2001; Wetmore 2001; Nimis & Martellos 2003; Obermayer 2004).

Bipolar

Illustrations : Wirth (1987: 106; 1995b: 240); Dobson (1979: 142; 1992: 189; 2000: 215 – as Leproplaca xantholyta); Wetmore (2001: 5, fig. 9).

Caloplaca xantholyta is characterised by: the saxicolous habit (acid and basic rocks); its yellow pulverulent thallus with marginal lobes that react K+ violet-red (see above under C. chrysodeta); and by the thick, white medulla. It is distinguished from C. citrina by its thicker, leprose thallus with mounded ridges, a thicker, white cottony medulla; and somewhat lobed margins (Wetmore 2001: 6).