Everniastrum Hale ex Sipman
Type : Everniastrum cirrhatum (Fr.) Hale ex Sipman [=Parmelia cirrhata Fr.]
Description : Thallus foliose, loosely attached to substratum, 4–30 cm diam. Lobes linear, subdichotomously to dichotomously branched, moderately to weakly canaliculate to involute, narrow, 0.5–4 mm wide, with or without marginal cilia. Cilia simple or branched, black. Upper surface pale-grey to green-grey (atranorin and chloroatranorin), sometimes grooved or maculate, without pseudocyphellae, with or without soredia and isidia. Upper cortex paraplectenchymatous with a pored epicortex; cell walls with isolichenan. Medulla white. Photobiont green, Trebouxia. Lower surface with channels, rhizinate or glabrous, black or brown. Rhizines dichotomously branched, more rarely squarrose or simple, black or brown-black. Ascomata apothecia, laminal; pedicel short, hollow; disc imperforate; thalline exciple without cilia. Asci relatively large (c. 50 × 23 μm), 8-spored. Ascospores simple, colourless, ellipsoidal, 7–28 × 5–10 μm. Conidiomata pycnidia, laminal, immersed. Conidia colourless, bifusiform (4–8 × 0.7 μm) or filiform (13–20 × 1 m).
Everniastrum is a pantropical genus of some 31 species (Kirk et al. 2001) of mainly tropical distribution included in the family Parmeliaceae (Eriksson et al. 2004; Pennycook & Galloway 2004; Eriksson 2005). It is discussed by Sipman (1986a: 237–238), Elix (1994f: 37–38), Kurokawa (1999b – as Cetrariastrum), Kurokawa & Lai (2001: 233–236 – as Cetrariastrum) and Nash et al. (2002a). Species are found both on bark and on rock. One species occurs in New Zealand, treated earlier in the Flora (Galloway 1985a: 83–84) as Cetrariastrum.
