Flora of New Zealand Series

Thallus foliose, dorsiventral, heteromerous, lobate, corticolous or saxicolous. Lobes sublinear, narrow, apically truncate. Upper surface with or without isidia, with or without soredia, with or without maculae, pseudocyphellae absent, whitish-grey to yellowish. Medulla white. Photobiont green, Trebouxia. Lower surface uniformly black, rhizinate. Rhizines black, dichotomously branched, conspicuous and often projecting beyond margins. Apothecia lecanorine, uniformly small, 1-5 mm diam., sessile, disc imperforate. Ascospores simple, colourless, 4-10 × 8-16 µm, 8 per ascus.

Hypotrachyna is a segregate of Parmelia Ach., [Hale Phytologia 28: 340-342 (1974); Smithson. Contr. Bot. 25: 1-73 (1975)]. It contains c. 100 species most of which are of tropical, montane distribution. The group has a very diverse chemistry [Hale loc. cit. (1975); Krog and Swinscow Norw. J. Bot. 26: 11-43 (1979)]. Ten species are recorded from New Zealand.