Flora of New Zealand Series

Type : Melanelia stygia (L.) Essl. [=Lichen stygius L.]

Description : Thallus foliose, loosely to tightly adnate. Lobes irregular to sublinear, 0.5–6 mm wide, with eciliate margins. Upper surface brown to brown-black (K− and HNO3+ or HNO3+ pale-red), emaculate, with or without pseudocyphellae, isidia, soredia and cortical hairs; upper cortex paraplectenchymatous, with a non-pored epicortex. Cell walls containing isolichenan. Medulla loosely packed, white. Photobiont green, trebouxioid. Lower surface pale-tan to black; rhizines mostly simple, rarely furcate or penicillate at apices, tan to black. Ascomata apothecia, laminal, sessile or rarely shortly pedicellate; disc concave to flat, imperforate, red-brown to brown-black. Ascospores ellipsoidal, 8 per ascus, 10–20 × 7– 10 μm. Conidiomata pycnidia, laminal, immersed. Conidia fusiform to weakly bifusiform, 5–8 × 1 μm.

Melanelia s. lat., included in the family Parmeliaceae (Eriksson et al. 2003; Pennycook & Galloway 2004) until very recently, comprised 42 species (Kirk et al. 2001), common in temperate and boreal areas of the Northern Hemisphere. As originally defined (Esslinger 1977b, 1978a) the genus was heterogeneous, the anomalous Parmelia acetabulum -group later being segregated as the genus Pleurosticta (Lumbsch et al. 1988). Species of Melanelia in this more restricted sense were characterised by a brown upper cortex (HNO3− ) that is commonly pseudocyphellate in part or has cortical hairs; and isolichenan in the cell walls (Elix 1993a). A new species was described from New Zealand by Galloway & Jørgensen (1990). Further information on the genus is contained in the following: Esslinger (1990, 2002a), Elix (1994j), Thell (1995), Kashiwadani et al. (1998) and Kantvilas et al. (2002). A recent molecular study using sequence data from 10 species of Melanelia from Poland and the Czech Republic (Guzow-Krzemińska & Węgrzyn 2003) disclosed three clades and suggested, along with data reported by Crespo et al. (1999), that Melanelia may not be monophyletic. Work very recently published (Blanco et al. 2004a), based on molecular and morphological data of species of Melanelia s. lat., shows that Melanelia s. str. comprises a small group of saxicolous lichens related to the type, M. stygia, and having bifusiform conidia. The remaining species studied were primarily corticolous with mainly cylindrical to filiform conidia, and belong to two separate clades that are recognised as two new genera named Melanelixia and Melanohalea. The epicortex of species in Melanelixia has pores or special "fenestrations", while species in Melanohalea are pseudocyphellate. Pending further studies on the group, three species are here retained in Melanelia, with M. inactiva and M. zopheroa transferred to Melanohalea (q.v.).