Flora of New Zealand Series

Thallus crustose or subsquamulose, thin, strongly convex-areolate, muscicolous, terricolous or saxicolous. Photobiont green, Protococcus. Apothecia black, between thalline areolae, lecideine, flat, strongly marginate. Ascospores 8 per ascus, spindle-shaped or acicular, more than 2-septate.

Arthrorhaphis is found on soil, and amongst moss on rocks in alpine habitats. Distribution of the genus is arctic-alpine in Europe and North America. It is a bipolar genus of c. 7 species included in the family Arthrorhaphidaceae [Poelt and Hafellner Phyton, Horn 17: 213-220 (1976)], one of which is known from island groups in the southern Indian Ocean viz.: Marian, and Prince Edward Is [Lindsay Nova Hedwigia 28: 667-689 (1977)] and from New Zealand [Galloway and Simpson N.Z. J. Bot. 16: 511 (1978)]. Species of Arthrorhaphis are often included in the genus Bacidia [See Laundon Lichenologist 2: 62-63 (1962)].