Rhizocarpon hochstetteri s. str. is shown to be an upland/montane species with relatively large ascospores. The name Rhizocarpon infernulum is resurrected for the species with smaller ascospores previously included within R. hochstetteri, but which is probably more closely related to R. cinereovirens. Lectotypes are chosen for a number of taxa, including R. cinereovirens and R. infernulum, and descriptions provided for two new taxa with small hyaline, 1–septate ascospores: R. caesium, which occurs on damp, mildly basic rocks in oceanic areas, and R. infernulum f. sylvaticum occurring on siliceous rocks in damp deciduous woodlands. All these taxa are known also from North America. Rhizocarpon discoense is shown to be a distinct species, not a synonym of R. cinereovirens. The different ascospore dimensions reported for R. hochstetteri by British and European authors are shown to be due to confusion between R. hochstetteri and R. polycarpum. A number of morphological characters are evaluated regarding their relevance to species separation in Rhizocarpon and the name Macrocarpa-green is proposed for the olivaceous pigment present in most species of Rhizocarpon and Porpidia. A key is provided for the species of Rhizocarpon with hyaline, 1– septate ascospores.

Lasallia hispanica (Frey) Sancho & Crespo comb. nov. is proposed as a result of anatomical and morphological comparisons between it and the related species, L. brigantium Zsch. and L. rossica Dombr. For all three species ecological notes, data on world distributions, and a key are provided.

Thamnolia vermicularis is a globally widespread arctic-alpine lichen with two distinct chemotypes. The intermixing of these chemotypes at the local scale and lack of genetic variation between them is puzzling given the apparent absence of specialized reproductive structures. Apothecia and conidiomata were originally reported for Thamnolia in the second half of the 19th century, but putative apothecia proved to be parasitic in origin. This study presents conclusive microscopic evidence for the existence of pycnidial conidiomata containing conidia on thalli of Thamnolia vermicularis from geographically widespread locations. Sequences of the internal transcribed spacer (ITS) region of ribosomal DNA from excised pycnidial conidiomata matched that of thallus tips from individual Thamnolia thalli. Our examination of the historic literature found that the occurrence of pycnidial conidiomata was never disproved, but this information was lost from the post-1920s English-language literature. Our rediscovery of pycnidial conidiomata indicates that Thamnolia vermicularis possesses a reproductive strategy with the potential for long-distance dispersal of multitudes of mitotically produced conidia, providing a plausible explanation for the cosmopolitan distribution of the species and the low levels of genetic variation among populations. Reversible processes, for example alternative splicing, warrant consideration as explanations for chemotype intermixing.

The genus Mycoblastus in cool temperate latitudes of the Southern Hemisphere is reviewed. Eight species are treated in detail: M. bryophilus Imshaug ex Kantvilas sp. nov., from Campbell Island and Tasmania; M. campbellianus (Nyl.) Zahlbr., M. coniophorus (Elix & A.W. Archer) Kantvilas & Elix comb. nov. and M. dissimulans (Nyl.) Zahlbr., all widespread across the austral region; M. disporus (C. Knight) Kantvilas comb. nov., from New Zealand and Tasmania; M. kalioruber Kantvilas sp. nov, from Tasmania; M. sanguinarioides Kantvilas sp. nov., from Tasmania and south-eastern Australia; and M. leprarioides Kantvilas & Elix sp. nov., from south-eastern Australia (Victoria). Notes are provided on many other species of Mycoblastus, including those recognised for the Northern Hemisphere, and those originally described from austral regions but now excluded from the genus. Major characters of the genus are discussed, including thallus morphology and chemistry, apothecial pigments and ascus structure. It is suggested that the genus is heterogeneous and that some of its closest affinities may lie with the family Megalariaceae and the genus Japewia.

Rinodina brasiliensis, a corticolous isidiate species with large Pachysporaria-type ascospores is described from south-eastern Brazil. The new species is closely related to R. dolichospora and to R. guianensis.Rinodina confinis is a synonym of R. dolichospora. Notes on the taxonomy, morphology, anatomy, chemistry and distribution of these three taxa are given. Descriptions and iconography are provided. A key to species is also included.

Aspicilia fluviatilis and A. granulosa, two arctic and/or (sub)alpine species with elongate ± diverging and ± branching marginal areoles, are described as new and compared with similar species occurring in Fennoscandia. A parsimony analysis based on ITS indicates a close relationship with the mainly coastal A. epiglypta. Aspicilia epiglypta, A. disserpens and A. sublapponica are lectotypified and A. disserpens is reduced to synonymy with A. perradiata. Aspicilia alboradiata and A. circularis are excluded from the Fennoscandian lichen biota. A key to Fennoscandian Aspicilia species with radiating thalli and/or elongate ± diverging and ± branching marginal areoles is also presented.

Five new species of the genus Polymeridium are described from Brazil. All exhibit at least one character that was previously unknown in the genus: P. corticatum has a corticate thallus and 2 ascospores per ascus, P. immersum has the ascomata deeply immersed in the bark under the thallus, P. isohypocrellinum has a red, KOH+ green pigment (iso-hypocrellin) in the ostiole, P. julelloides has short and broad muriform (Julella-like) ascospores, and P. paraproponens has ascomata in groups of two to three. Brazil is clearly the centre of diversity of the genus. Iso-hypocrellin is a new substance for the genus.

In the recently deglaciated zone of a valley glacier in Central Ellesmere Island the mean period of time before the onset of colonization on bare rock surfaces was estimated to be about 80 years. The first species to establish was Xanthoria elegans, followed by Lecanora crenulata and Umbilicaria virginis approximately 20 years later. Summer temperature appeared to be one factor which affected lichen establishment in recently deglaciated bare areas in the High Arctic. Warmer microsites were identified as preferred locations for thallus establishment; these, therefore, constitute ideal sites for studies of thallus initiation under natural conditions. Following the retreat of a glacier from its most advanced Little Ice Age position, 16 species of saxicolous lichens have become established on bare rock debris in the icefree zone, but in nine transects only five species had a constancy of 80% or more. Lichen diversity in this successional photocommunity was comparable to that in a nearby pre-Little Ice Age landscape with more varied substrata.

Factors affecting the outcome of a PCR is discussed. Nested PCR is described and a protocol that has been shown to work well for the amplification of ribosomal genes in ascomycetes is described. It is claimed that DNA extracts of lichenized fungi, contrary to many other organism groups, are often contaminated by other fungi. This poses a problem due to the preferential amplification of short intron-lacking sequences over longer, intron-containing ones, particularly when extension time is limited. A simple protocol for optimizing and troubleshooting PCRs is presented.

Culture experiments that trigger the axenically grown mycobionts of Lecanora rupicola to produce the polyketide chemosyndrome typical of the naturally grown lichen are reported. This chemosyndrome comprises lecanoric, haematommic and orsellinic acids, sordidone, eugenitol and atranorin, all of which were hardly produced under standard culture conditions. The only exception was arthothelin that was only present in the voucher specimen. It has been shown that almost the complete acetyl-polymalonyl-pathway leading to depsides and chromones can be induced in culture, but apparently not the xanthones. The mycobiont was also successfully re-synthesized with its original photobiont, as confirmed by Scanning Electron Microscope studies (SEM). Cultures of the resynthesised lichen biosynthesized additional satellite substances, which were not detected either in the voucher specimens or in the aposymbiontically (without the photobiont) grown mycobiont cultures. The identity of cultured mycobionts of L. rupicola was confirmed by comparing ITS-DNA-sequence data from the original lichen with publicly available (GeneBank) sequences of that species.

In continuation of our ongoing revisionary studies on the lichen family Graphidaceae from India, a treatment of 25 species of the lichen genera Fissurina and Hemithecium from India is presented. In our earlier work on the lichen genus Fissurina, 16 species were reported from India. In the present study, 17 additional species of Fissurina from India are recognized. Nine species, viz. Fissurina andamanensis, F. disposita, F. immersa, F. indica, F. microcarpa, F. nicobarensis, F. simplex, F. sporolata, and F. submonospora, are described as new to science. Seven species, viz. Fissurina canlaonensis, F. cingalina, F. comparimuralis, F. monospora, F. nitidescens, F. rubiginosa, and F. subnitidula, are recorded for the first time from India. One species, Fissurina sp. 1, is recorded but not formally described as new due to scanty material. Eight species in the lichen genus Hemithecium, including three new species, viz. H. kodayarense, H. longilirellatum, H. verrucosum, and five new combinations, viz. Hemithecium andamanicum, H. flabillatum, H. flavoalbum, H. flexile, and H. norlabiatum, are also recognized in the present work. A revised key for the identification of all 33 species of Fissurina and 26 species of Hemithecium so far known from India is provided.

The value of primary chemical compounds correlated with known secondary chemistry and morphological variation within the Ramalina siliquosa group has been investigated. A hundred specimens were collected on two different occasions from 13 different populations on the Swedish west coast during April 1984. Protein extracts were prepared from 27 on secondary constituents identified and morphologically analysed populations. The protein bandings were performed by means of isoelectric focusing. Twenty-two different banding patterns were analysed since two were destroyed during preparation and three others yielded weak patterns. The results indicated that three different banding pattern types could be discerned: type A originated from material containing norstictic acid, stictic acid, norstictic acid in combination with stictic acid and on acid-deficient material; type B originated from material containing salazinic acid or salazinic acid in combination with protocetraric acid; and type C originated from material containing salazinic acid, protocetraric acid, salazinic acid in combination with protocetraric acid or on acid-deficient material. Material of banding type A belonged morphologically to R. cuspidata (Ach.) Nyl. and material of banding types B and C to R. siliquosa (Hudson) A. L. Smith. Seasonal and developmental factors can, however, affect the production of both primary and secondary constituents. Since there are no obvious morphological differences between the different chemical races within R. siliquosa s. str. and as material of salazinic acid in combination with protocetraric acid yielded both type B and type C banding patterns, the results do not support a taxonomy in the R. siliquosa group recognizing more than two species.

Caloplaca concreticola is described here as new. It is a morphologically well-characterized, sorediate species of the subgenus Pyrenodesmia, that comprises a part of the ‘‘black-fruited’’ taxa with an absence of anthraquinones in their apothecia. Currently it is known only from concrete and always occurs close to water (mainly on the walls of water channels). Analysis of nuclear ribosomal ITS sequence data of the new species, together with most European species of the subgenus, supports the recognition of the new species as a monophyletic taxon within the Pyrenodesmia clade.

The new genus Labrocarpon is introduced for the species Melaspilea canariensis based on the presence of excipular periphysoids. In addition, Buelliella protoparmeliopsis is described from Chile, the twelfth species of the genus. Notes on the two new taxa and related species are provided.

The new species Coniarthonia aurata E. L. Lima, M. Cáceres & Aptroot, Cresponea endosulphurea A. A. Menezes, M. Cáceres & Aptroot, Cryptothecia macrocephala E. L. Lima, M. Cáceres & Aptroot, and Synarthonia sarcographoides Aptroot, A. A. Menezes, E. L. Lima & M. Cáceres are described from Caatinga vegetation in NE Brazil. They were found in the Chapada do Araripe in the state of Ceará and/or the Vale do Catimbau National Park in Pernambuco. Coniarthonia aurata has weakly organized, semiglobose apothecia with golden crystals, and on first impression looks like the anamorph of a Tylophoron. Cresponea endosulphurea has a pigment of the group of xantholepinones in the thallus. It is the first time that a substance from this group is reported from the Arthoniales. Cryptothecia macrocephala has strongly macrocephalic ascospores and contains psoromic acid in the thallus. Synarthonia sarcographoides is only the third species in this rarely found genus. It is characterized within the genus by muriform, brown ascospores, but it is assigned with hesitation to the genus. It is locally quite common.