Flora of New Zealand Series

Thallus crustose, to dwarf-fruticose, or granular, isidiate or not, sorediate or not, creamish-white, or greyish or pinkish-grey or yellowish-grey, often with a pale, marginal prothallus, corticolous or saxicolous or terricolous. Photobiont green, Myrmecia. Cephalodia laminal, containing Calothrix. Apothecia sessile or ± innate, single or 2-3 sunk in spherical thalline warts, discs closed as in perithecia, with a thin, hyaline wall and vertical ostiole. Asci short, (4-)6-8 spored. Ascospores relatively large, colourless, simple, ellipsoid.

Coccotrema is a genus of c. 8 described species of which two occur in New Zealand. It is treated as Perforaria Müll. Arg., by some authors [see Oshio J. Sci. Hiroshima Univ. ser. B. Div. 2 (Bot.) 12: 81-163 (1968)] but this is a later homonym of Coccotrema. It is included in the family Pertusariaceae by some authors, but Brodo [ Bryologist 76: 260-270 (1973)] claims that its true relationships are still unclear. Species of Coccotrema occur mainly around the Pacific basin, usually in oceanic and suboceanic places (Brodo loc. cit. ). Both species known from New Zealand have a widely disjunct distribution, paralleled by species of Siphula, Placopsis and Sphaerophorus.