Per G. Ihlen’s research while affiliated with Umeå University and other places

Dactylospora aeruginosa Holien & Ihlen, sp. nov. is described from Norway and U.S.A. and D. borealis Holien & Ihlen, sp. nov. is described from Norway, Sweden, and U.S.A. Both species are lichenicolous, but D. aeruginosa is also saprobic on wood and bark of Picea abies and Juniperus communis, whereas D. borealis is only rarely growing on bark of P. abies. Notes are given on their ecology and distribution. A key to the known lichenicolous species of Dactylospora occurring in Scandinavia is included. Lichenodiplis lecanorae is suggested to be the anamorph of D. borealis.

Two lichenicolous species are discussed: the recently described Unguiculariopsis nephromae, which occurs on Nephroma species in Canada, Fennoscandia, North America and Russia, is combined into Protounguicularia; and Hyalopeziza rapax sp. nov. is described from Pseudocyphellaria crocata in Alaska. In discussing generic placements, it is concluded that the species now known as Olla transiens is better accommodated in Protounguicularia and the species is combined into that genus. Attention is drawn to variability in general appearance of P. nephromatis, particularly the occurrence of both superficial and erumpent apothecia in the same species.

An annotated key to the lichenicolous (lichen-inhabiting) Ascomycota, including mitosporic morphs, known from Sweden is presented. Recent additions, both from the literature and our own collections, of these fungi to the Swedish flora are also included. A total of 298 ascomycetes representing 83 genera, and 65 mitosporic fungi from 31 genera, have been found to occur in Sweden. Each species keyed out is followed by information and selected literature references on morphology, distribution, and ecology. Taxonomic notes and discussions are given for several critical genera and species, and selected species are illustrated.

The taxonomic and nomenclatural status of the common Scutula (Ramalinaceae, Lecanorales, Ascomycota) parasitizing species of Solorina (Peltigeraceae, Lecanorales) is clarified. The type of Biatorina tuberculosa Th. Fr., which, according to the protologue, was described from a Peltigera, is actually growing on Solorina saccata, and the correct name for this species is here shown to be Scutula tuberculosa (Th. Fr.) Rehm. Lectotypes are designated for Lecidea solorinaria Nyl., Scutula krempelhuberi Körb. and Lecidea solorinicola Vain. Notes on the taxonomy and classification of the genus are given, and a key to the species of Scutula s. str. in the Northern Hemisphere is presented. Scutula tuberculosa is reported as new to Asia and North America.

The new fungus Cercidosporaalpina is described from Sweden where it grows on the thallus of the crustose lichen Stereocauloncumulatum. The ecology and distribution of the new species as well as its morphological similarities to related species are discussed. A key to the known species of Cercidospora occurring in Fennoscandia is provided.

Species richness patterns of ground-dwelling vascular plants, bryophytes, and lichens were compared along an altitudinal gradient (310-1135 m a.s.l.), in western Norway. Total species richness peaked at intermediate altitudes, vascular plant species richness peaked immediately above the forest limit (at 600-700 m a.s.l.), bryophyte species richness had no statistically significant trend, whereas lichen richness increased from the lowest point and up to the forest limit, with no trend above. It is proposed that the pattern in vascular plant species richness is enhanced by an ecotone effect. Bryophyte species richness responds to local scale factors whereas the lichen species richness may be responding to the shading from the forest trees. (c) 2006 Elsevier SAS. All rights reserved.

The new lichenicolous species Epicladonia lapponica Ihlen and Telogalla physciicola Ihlen & R. Sant. are described from Sweden. Arthonia digitatae Hafellner and Phaeospora arctica Horáková & Alstrup are reported as new to Scandinavia and Cercidospora cecidiiformans Grube & Hafellner and Pronectria xanthoriae Lowen & Diederich are reported new to Sweden. Notes have been given on the ecology of these species. German Die neuen lichenikolen Arten Epicladonia lapponica Ihlen und Telogalla physciicola Ihlen & R. Sant. werden für Schweden beschrieben. Neu für Skandinavien werden Arthonia digitatae Hafellner und Phaeospora arctica Horáková & Alstrup beschrieben und für Schweden Cercidospora cecidiiformans und Pronectria xanthoriae Lowen & Diederich. Anmerkungen zur Ökologie dieser Arten sind enthalten.

While studying the taxonomy of the non-yellow species of Rhizocarpon DC., with hyaline and muriform ascospores, in the Nordic countries (Ihlen 2004), some specimens of Rhizocarpon from the Svalbard archipelago were also examined. Among this material, we discovered six specimens of Rhizocarpon anaperum (Vain.) Vain. that had been labelled “ R. obscuratum ”. As R. anaperum is not listed in the recent checklist from Svalbard (Elvebakk & Hertel 1996) or, to our knowledge, in any other paper dealing with the lichen flora of Svalbard, it is here reported new to this archipelago.

The taxonomy of the non-yellow species of the genus Rhizocarpon (Rhizocarpaceae, lichenized Ascomycota) occurring in the Nordic countries, with hyaline and muriform ascospores, has been revised. Rhizocarpon amphibium, R. anaperum, R. distinctum, R. furfurosum, R. lavatum, R. petraeum, R. postumum, R. reductum, R. roridulum, R. rubescens, R. subgeminatum, R. sublavatum (reported from the study area for the first time), R. subpostumum, R. suomiense, R. timdalii, and R. umbilicatum are recognized. Their morphology, anatomy, secondary chemistry, ecology, and distribution in the Nordic countries are investigated and discussed. Distribution maps and a key to the species are provided. The most important characters for separating the treated species are pruinose/epruinose thallus, number of ascospores in asci, ascospore size and number of cells per ascospore in optical view, insoluble lichen pigments of the epihymenium and the proper excipulum, and lichen substances. Seven names are lectotypified and two are neotypified.

The new lichenicolous species Lichenostigmasupertegentis is described from Sweden and Norway where it grows on thalli and apothecia of Aspiciliasupertegens. The ecology and distribution of the new species are discussed and a distribution map is provided. The concept of Lichenostigma is enlarged to accommodate fungi producing macroconidia.