Calicium robustellum Nyl.
* Account prepared by Dr L. Tibell (Uppsala).
Thallus episubstratic, verrucose or rarely almost immersed, straw yellow to greenish-yellow. Apothecia robust, with short stalks, 0.35-0.60 mm high, epruinose, 1.7-2.4 times as high as width of stalk. Surface of mazaedium sometimes with a faint white pruina. All parts of stalk I-. Capitulum obconical, 0.24-0.44 mm diam. Excipulum of short, cylindrical to isodiametric, dark brown, heavily sclerotized cells, interhyphal spaces filled with sclerotic material. Hypothecium blackish brown with slightly convex upper surface. Stalk thick, black, epruinose, 0.16-0.28 mm diam. Central part of stalk of periclinally arranged, dark brown hyphae, c. 3 µm diam., with sclerotized walls but without interhyphal sclerotized material. Outer layer of stalk pale brown to aeruginose or translucid, consisting of anticlinally arranged, branched hyphae with swollen, gelatinous walls but not sclerotized. A thin gelatinous, I-, coat is sometimes found enclosing the stalk. Asci cylindrical, 44-53 × 4.5-5.3 µm, with uniseriate spores. Ascopores ellipsoid, 12.5-15.5 × 6.5-7.5 µm, with minutely warted to areolate ornamentation. Chemistry: Thallus containing arthothelin, thuringione, and thiophanic acid. Thallus K+ dull yellow, C+ orange, KC+ orange to red, Pd-, UV+ dark orange.
N: North Auckland, Rodney County. Rare, only known from one locality. On lignum close to the sea. Collected by J.K. Bartlett.
Australasian
C. robustellum was described from New Caledonia and occurs also in Eastern Australia. It occurs only in the Southern Hemisphere.
