Flora of New Zealand Series

Lichen inquinans Sm. in Sm. et Sowerby, Engl. Bot. 12: 810 (1801).

Pyrgillus crassus J. Murray, T.R.N.Z. 88: 184 (1960).

Pyrgillus crassus. Holotype: New Zealand. Otago, Green Hill (Silver Peaks). On line of old fenceposts. J. Murray 4203 OTA!

Thallus verrucose to cracked-areolate, pale to dark grey, usually rather thick, but sometimes almost immersed. Apothecia sessile or somewhat immersed, 1-2.5 mm diam., frequently with a faint, white pruina at edge of excipulum.. Excipulum thick, of densely interwoven, heavily sclerotized cells, strongly thickened at base. Laterally the excipulum consists of more distinctly reticulate, largely anticlinally arranged hyphae. Hypothecium blackish-brown, of vertically arranged hyphae. Asci cylindrical, stalked, spores uniseriate 45-55 × 5-7 µm. Ascospores broadly ellipsoid, dark brown, 14-19 × 8-11 µm, the surface finely striated, but also with a few irregular cracks. Chemistry: The thallus contains atranorin and usnic acid and reacts K+ yellow to reddish-brown, C-, Pd+ yellow.

S: Otago. Only known in one collection from Silver Peaks. On lignum of fencepost, c. 600 m.

Cosmopolitan

C. inquinans is widely distributed in the Northern Boreal - Temperate Zones of the Northern Hemisphere. The single noted occurrence on a man-made substrate in New Zealand strongly suggests that the species was introduced with sheep from England, where it is rather common in similar habitats in south-eastern parts.