Calicium salicinum
* Account prepared by Dr L. Tibell (Uppsala).
Thallus endosubstratic, often staining substrate grey. Apothecia 0.9-1.5 mm high, with a brown pruina on lower side of excipulum and sometimes upper part of stalk, 7-15 times as high as width of stalk. All parts of stalk I-. Capitulum lenticular, 0.25-0.40 mm diam. Excipulum of ± isodiametric, heavily sclerotized cells, dark brown; outer surface covered by a layer of granular, reddish-brown crystals that yield feather to plate-like, violet-red crystals in K. Hypothecium blackish-brown with convex upper surface. Stalk black, sometimes with a brown pruina in uppermost part, 0.08-0.12 mm diam. Central part of stalk of densely intertwined, dark brown hyphae, c. 3 µm diam., but without interhyphal sclerotized material. Outer part of stalk slightly paler and a gelatinous I-, coat often covers the stalk. Asci cylindrical, 34-41 × 3-4 µm, with uniseriate spores. Ascospores ellipsoid, 7-11 × 3.5-5 µm with ornamentation of spirally arranged ridges and occasional irregular cracks. Chemistry: Thallus containing norstictic acid. Thallus K+ dull yellow, C-, KC+ dull yellow, Pd+ yellow to orange. These reactions though, are not detected in all specimens. Pruina K+, forming violet-red feather to platelike crystals (seen in watermounts on addition of K).
N: South Auckland, Gisborne, Hawke's Bay, Wellington. S: Nelson, Marlborough, Canterbury, Otago. Not very common on decorticated stumps of old trees in rather shaded and sheltered localities, more rarely on bark of Nothofagus; 150-900 m.
Cosmopolitan
A species of wide distribution in the Northern Boreal - Subtropical Zones of the Northern Hemisphere.