Chaenotheca ferruginea (Turner ex Sm.) Mig.
*Account prepared by Dr L. Tibell (Uppsala).
Calicium ferrugineum Turn. ex Sm., Engl. Bot. 35: 2473 (1812).
Thallus immersed, or usually episubstratic, granular to verrucose, palegrey or whitish, often with limited yellow to reddish patches turning deep red in K. Photobiont: Trebouxia. Apothecia epruinose, short or long, 0.8-1.7 mm high, 7-19 times as high as width of stalk. Stalk 0.07-0.15 mm diam., shining, black, epruinose. Capitulum broadly or narrowly obconical, with well-developed excipulum. Excipulum 0.23-0.47 mm diam. Hypothecium obconical with convex surface. Capitulum without pruina. Asci cylindrical to narrowly clavate, 14-18 × 2.7-3.3 µm well-stalked, spores uni-or biseriate. Usually asci are formed singly but sometimes two asci join into a short chain. Ascospores spherical, 5.6-7.7 µm diam., when mature provided with coarse and irregular fissures. Chemistry: The thallus of C. ferruginea frequently contains a yellow-red pigment, which is often concentrated in distinct patches. The pigment is K+ dark red and probably of quinonoid nature. A yellowish, K+ red pigment also occurs in the mazaedium and often gives the mazaedium a strikingly yellow tinge. Parts of the thallus without the yellow pigment are K-, KC-, C- and Pd-.
N: Gisborne, Wellington. S: Nelson, Otago, Southland. C. ferruginea seems to be rather rare on the Central Plateau of North I; and in South I. It occurs only on decorticated stumps, particularly of Nothofagus, 100-930 m.
Cosmopolitan
In the Northern Hemisphere C. ferruginea is widely distributed in the Middle Boreal - Temperate Zones. In parts of Western Europe it seems to be quite resistent to air pollution and is mainly found on bark.
