Dirinaria (Tuck.) Clem.
Thallus foliose, dorsiventral, heteromerous, closely attached to sub-strate, suborbicular to spreading, corticolous or saxicolous. Lobes narrow, radiating, pinnate, subpinnately-dichotomous to subdichotomous, discrete or confluent at margins, centrally confluent, eventually verrucose to subcrustose. Upper surface glaucous-grey, glaucous-white, pale grey to dark grey, smooth or wrinkled, with or without soredia, with or without pruina. Medulla white or pale yellow in upper part, occasionally reddish. Photobiont green, Trebouxia. Lower surface corticate, of longitudinal, thick, brown hyphae, black, rarely pale grey to grey, without rhizines. Apothecia sessile to subpedicellate, lecanorine, disc black, epruinose occasionally lightly grey-or purple-pruinose, margins distinct, well-developed, with persistent algal cells at the upper edge or along the greater part of the thalline exciple. Ascospores 8 per ascus, brown to dark brown, thick-walled, 1-septate, ellipsoid to elongate-ellipsoid, not constricted at centre.
Dirinaria is a mainly tropical genus of c. 26 species included in the family Physciaceae [Awasthi Biblthca lich. 2: 1-108 (1975)]. Dirinaria has greater affinity with Buellia, Rinodina and Pyxine than it does with Physcia, Physconia, Hyperphyscia, Anaptychia and Heterodermia [Awasthi, loc. cit. , Swinscow and Krog Norw. J. Bot. 25: 157-168 (1978)]. The lack of rhizines distinguishes Dirinaria from Pyxine and Physcia, also the lobes are applanate and marginally confluent, and no such confluence occurs in either Pyxine or Physcia. Two species are known from New Zealand from predominantly northern, coastal habitats, but the genus is still much in need of collection and study here.
