Xanthoria (Fr.) Th.Fr.
Thallus foliose, lobate, dorsiventral, heteromerous, orbicular, ± rosette-forming to spreading, loosely to closely attached. Upper surface corticate, bright yellowish-orange or orange-red (K+ purple - parietin), smooth or wrinkled, matt or shining. Photobiont green, Trebouxia. Medulla white. Lower surface corticate, white to pale brownish, sparingly rhizinate. Rhizines simple, pale. Apothecia lecanorine, sessile to subpedicellate, disc plane or concave, yellow, orange or orange-red, epruinose. Ascospores 8 per ascus, colourless, polarilocular. Pycnidia laminal, immersed in ± prominent warts.
Key
Xanthoria, included in the family Teloschistaceae, contains c. 15 species, some of wide distribution. Four are known in New Zealand†, ranging from s.l. to 1700 m, and colonising bark, rocks, glass, tile and slate. Australasian taxa are discussed by Murray [ T.R.S.N.Z. 88: 198-202 (1960)] and Filson [ Muelleria 2: 83-86 (1969)].
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† Xanthoria candelaria (L.) Th. Fr., is also known from New Zealand. Collected from Hihitahi State Forest (on Dacrydium cupressinum) by J.K. Bartlett.