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The new species Oropogon evernicus Essl. & S. Leavitt and O. protocetraricus S. Leavitt & Essl. are described from montane regions of Central America, further increasing the diversity of this genus in the New World. Oropogon evernicus is separated from O. americanus by the presence of medullary tissue directly beneath the pseudocyphellae, while O. protocetraricus is separated from O. caespitosus by the presence of protocetraric acid. The segregation of both species is confirmed by molecular sequence data (nuclear ITS, nuLSU, and β-tubulin). Both species appear to have split from their most recent common ancestor during the Miocene, supporting Miocene-dominated diversification of neotropical Oropogon species found in Central America.
This paper continues a revision of generic concepts in the parmelioid lichens using molecular data in order to reach a consensus among lichenologists over which segregates proposed over the last two decades should be accepted. Here we employ data from three gene portions to provide a basis for a revised generic concept of the brown parmelioid lichens hitherto classified in Melanelia. The phylogeny was studied using a Bayesian analysis of a combined data set of nuclear ITS, LSU rDNA and mitochondrial SSU rDNA sequences. 173 new sequences were obtained from 38 specimens of 15 Melanelia species, 37 related parmelioid species, and eight non-parmelioid species. The results indicate that Melanelia is not monophyletic but falls into four different clades. The genus Melanelia is restricted here to a small group of saxicolous lichens related to the type species M. stygia, and with bifusiform conidia, while the remaining species, most of which are primarily corticolous and have mainly cylindrical to filiform conidia, belong to two other clades recognised as two new genera: Melanelixia and Melanohalea, to accommodate the M. exasperata and M. glabra groups, respectively. 27 new combinations are made. The epicortex of Melanelixia species have pores or special structures termed here ‘fenestrations’, while most Melanohalea species are pseudocyphellate. Pleurosticta links to the Melanohalea clade but without strong support, and the phylogenetic position of M. disjuncta and its related species remains uncertain, linking with the Xanthoparmelia (syn. Neofuscelia) clade but also without strong support.
A Bayesian analysis of nuclear ribosomal DNA internal transcribed spacer (ITS) sequences was used to infer phylogenetic relationships of 14 Physconia species. The analysis supports the monophyly of the genus. Three well supported clades can be distinguished within Physconia: the series griseae, venustae and pulverulentae. The relationships of these clades, however, is not resolved with confidence. Cortical characters are re-evaluated on the basis of the phylogenetic hypothesis. Anatomical features of the upper cortex are only diagnostic above the species level for two special forms of two-layered cortices, while morphological characters, such as lower surface and rhizine-type are characteristic for distinct clades. P. venusta and P. perisidiosa are not separated in this analysis, but populations of P. muscigena, and European and North American samples of P. americana are clearly distinct and the monophyly of both P. americana and P. muscigena s. lat. is rejected on the basis of a Bayesian hypothesis testing.
The morphology and chemistry of the type specimens for the four species of brown Parmelia described by A. N. Oxner have been studied. The correct name for the widely distributed Northern Hemisphere taxon, now generally known as Melanelia substygia (Räsänen) Essl. (Parmelia substygia Räsänen), is now M. tominii (Oxner) Essl. Parmelia borisorum Oxner and Parmelia altaica Oxner are also synonyms of M. tominii. Parmelia teretiuscula Oxner is a synonym of Melanelia stygia (L.) Essl.
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