bluuebunny/crossref_metadata_2025_split huggingface dataset:
Growth from the Centre in an Umbilicate Lichen
Authors: Hestmark Geir 
Published: September 2002

AbstractThe pustules on the surface of the umbilicate lichen Lasallia pustulata are moved away from the centre and towards the thallus margins with an average speed of 1.8 mm per year, revealing a growth pattern organized radially and flowing from the centre of the thallus. Pustules close to the margin move substantially faster than those close to the centre; for each 10 mm added to the initial distance from the centre, the speed of outward movement is about doubled. This suggests that intercalary growth over the entire thallus is displaced outwards in an accumulating manner, accelerating the pustules. Moving away from the centre the pustules expand, often collapse in the middle, and mature by developing isidia. In the less active (senescent ?) margins the pustules are eroded away and the supplementary intercalary growth seems insufficient to keep the outflowing thallus intact. Thus the margins are disrupted into irregular lobes.
The Phylogeny of Lecanactis (Opegraphaceae)
Authors: Tehler Anders , Egea José M. 
Published: September 2002

AbstractThe genus Lecanactis, with 24 species, has been phylogenetically analysed using cladistic parsimony methods and support tests. Morphological, anatomical and chemical data were used, comprising 38 characters. Twelve equally most parsimonious trees were obtained. The successive approximations character weighting method gave one most parsimonious tree. The ingroup, Lecanactis, is supported as monophyletic. Although parsimony jackknifing and Bremer support indicate that the trees are poorly supported, some groups are wholly or partly distinguished in both the strict consensus tree, the successive weighting tree and the Jac tree.
Protoparmelia Hypotremella, a New Sterile Corticolous Species from Europe, and its Lichenicolous Fungi
Authors: Aptroot A. , Diederich P. , van Herk C. M. , Spiers L. , Wirth V. 
Published: September 2002

AbstractProtoparmelia hypotremella van Herk, Spier & Wirth, a sterile corticolous lichen, is described as a species new to science, so far known from Austria, SW Germany and the Netherlands. It is rapidly spreading in Germany and the Netherlands. It is apparently close to P. oleagina, and is often found growing together with that species on oak trees along roads in the Netherlands. Both species are host to the lichenicolous fungi Sphinctrina anglica and Tremella wirthii.
Intraspecific Interactions and Parasitism in an Association of Rhizocarpon lecanorinum and R. Geographicum
Authors: Clayden Stephen R. 
Published: September 2002

AbstractIntraspecific thallus interactions in mixed populations of Rhizocarpon lecanorinum and R. geographicum in North Wales are described. In contrast to the most commonly occurring morphotype of R. geographicum, which forms mosaics comprised of sharply delimited individual thalli, R. lecanorinum thalli consistently merge with one another at intraspecific contacts, leaving no visible trace of their initial boundaries. On the analogy of mycelial interactions in populations of wood-rotting and other non-lichen-forming fungi, it is postulated that these differences are the outcome, in R. geographicum, of somatic incompatibility between distinct genotypes, and in R. lecanorinum of somatic compatibility among genetically identical or very closely related thalli. Possible mechanisms for the evolution of clonal population structure in R. lecanorinum and links between somatic interactions and reproductive output in these species are discussed. Facultative parasitism of R. lecanorinum by Schaereria fuscocinerea, and resistance to such parasitism by cooccurring R. geographicum, are also documented.
Population Structure of the Epiphytic Lichen Usnea Longissima in a Boreal Picea Abies Canopy
Authors: Gauslaa Yngvar 
Published: September 2002

AbstractUsnea longissima was sampled in SE Norway on six main branches of one Picea abies, comprising its full vertical canopy range. Nearly all specimens (n = 781) were unattached and fragmented, in contrast with associated lichens. A combination of weak axes and lack of holdfasts resulted in a population of repeatedly displaced thalli, a similar situation as in ground-dwelling vagant lichens. Comparisons with a litterfall population indicated that thalli, regardless of size, had a similar probability to end as litter on the ground. Specimens were frequently sorediate, but only 12 small thalli with a basal holdfast had been directly recruited through soredial establishment. Its patchy distribution within apparently homogenous forest stands is probably a consequence of a rare successful long-range dispersal through soredia coupled with an abundant local dispersal of coarse thallus fragments. Old forests with ample, diffuse skylight at lower and humid canopy levels are probably essential to maintain a vagant epiphytic life form with a predominantly downward dispersal of thallus fragments.
Visualization of Extracellular Deposits in Recent and Subfossil Umbilicaria Hyperborea
Authors: Fahselt Dianne , Alstrup Vagn 
Published: September 2002

AbstractField emission scanning electron microscopy was used to characterize mycobiont wall surfaces in Umbilicaria hyperborean from Greenland. To determine the precise intrathalline distribution of phenolics, comparisons were made of hyphal surface features and dimensions before and after acetone extraction. Stratification was evident within the medulla, as extracellular phenolics were observed only on hyphae near or within the algal zone. The outside diameter of hyphae in this region was thus significantly greater than in the remainder of the medulla. Surface deposits were also examined in 1350-year-old subfossil thalli and hyphal diameters were compared statistically to those in extant thalli. The mean hyphal diameter in the upper medulla was not significantly less in subfossil specimens than in recent thalli, suggesting that phenolic cover was maintained in spite of glaciation. However, after ice burial phenolic masses tended to be flatter than in recent specimens and finely tubcrculate. The appearance of mycobiont hyphae in the cortex of subfossil thalli seemed to be the same as in extant thalli, except that there tended to be more compressible, smaller and less conglutinated filaments near the algal layer.
Lichenicolous Fungi from the Western Pyrenees, France and Spain. IV. Ascomycetes
Authors: Etayo Javier , Diederich Paul 
Published: September 2002

AbstractTwenty species of lichenicolous ascomycetes are recorded for the western Pyrenees. Capronia hypotrachynae Etayo & Diederich (on Hypotrachyna species, also known from the Canary Islands and from Papua New Guinea), Llimoniella pubescens Etayo & Diederich (on Lepraria species, also from Scotland and Papua New Guinea), Polycoccum microcarpum Diederich & Etayo (on Cladonia species, also from Scotland), Skyttea megalosporae Etayo & Diederich (on Megalospora tuberculosa), Sphaerellothecium cinerascens Etayo & Diederich (on Cladonia parasitica) and S. parmeliae Diederich & Etayo (on Parmelia s. str., also from Finland) are described as new.
A New Species of Catillaria from Coastal Mediterranean Regions
Authors: Tretiach M. , Hafellner J. 
Published: September 2002

AbstractA revision of several specimens of Catillaria mediterranea Hafellner revealed that two species can be recognized: C. mediterranea s. str., which has 8–16 spores per ascus, grows on foliose and fruticose lichens, and has a Mediterranean- Macaronesian, montane distribution, and C. praedicta Tretiach & Hafellner sp. nov., which has (16-) 24–32 (-48) spores per ascus, occurs on shrubs in coastal Mediterranean maquis, and has a Mediterranean, maritime distribution. The systematic affinities of the two species with the 8-spored C. nigrodavata (Nyl.) Schuler are briefly discussed.
The Effect of Agronomic Photosystem-II Herbicides on Lichens
Authors: Jensen Manfred , Linke Kerstin , Dickhäuser Andreas , Feige G. Benno 
Published: September 2002

AbstractThe sensitivity of Hypogymnia physodes, Lobaria pulmonaria and Peltigera aphthosa to six photosystem II herbicides and to DBMIB was tested in the laboratory by chlorophyll fluorescence and oxygen-exchange measurements. In addition, experiments with freshly isolated photobiont cells from H. physodes and L. pulmonaria were performed. Generally, the lichens were most sensitive to the urea herbicides diuron and isoproturon, whereas the triazines atrazine, terbuthylazine, and simazine and the triazinone metamitron were less inhibitory. Among the three lichen species investigated, H. physodes was the most sensitive to the urea herbicides. For the other agents, no significant differences between lichen species could be found. The highest pI50 values obtained from dose response curves were around 6.5 for isolated photobionts, but most values for lichen thalli were in the range 5–6. Thus, there is no particular sensitivity of green algal lichen photobionts to photosystem II herbicides as compared to other algae, higher plant chloroplasts or protoplasts. In nature, we observed recovery from (damaging) treatment with 10−5 mol diuron 1−1 for H. physodes within weeks. Therefore, damage to lichens from the use of photosystem-II herbicides in agriculture is probably only of very local occurrence.
Lecanora Barkmaneana, a new Nitrophilous Sorediate Corticolous Lichen from the Netherlands
Authors: Aptroot A. , van Herk C. M. 
Published: September 2002

AbstractLecanora barkmaneana, a sorediate corticolous lichen belonging to the Lecanora subfusca group, is described as a species new to science on the basis of numerous sterile collections and two richly fertile collections. It is known so far only from the Netherlands, where it often grows on roadside trees. It seems to be spreading rapidly at nutrient-rich sites.
How Agriculture Affects Lichen Vegetation in Central Switzerland
Authors: Ruoss Engelbert 
Published: September 2002

AbstractThe results from several floristic and bioindication projects in Central Switzerland (1986–1998), focusing on the effects of agriculture, particularly from nitrogen and agrochemical emissions, are summarized. The abundance of nutrienttolerant lichen species and the decreased occurrence of nitrophytic lichens are both correlated with agricultural land use and high atmospheric deposition. The impact could be demonstrated not only by the distribution patterns of nutrient-tolerant species, but also by the high N content of lichens such as Physcia caesia. Positive growth response of Cetraria islandica to application of mineral nutrients and increased CO2 in open-top chambers at high altitudes was also observed. The methods and a survey of the results from studies conducted within the framework of the lichen research programme of the Natural History Museum of Lucerne are presented here. A discussion of the issues shows the need for further studies concerning the influence of introduced nutrients on the biodiversity of lichens.
The Response of Different Cladonia Species after Treatment with Fertilizer or Lime in Heathland
Authors: Vagts Irene , Kinder Michael 
Published: September 2002

AbstractThe effect of deposition of different fertilizers and of lime on lichens was investigated under field conditions. Three terricolous lichens were tested: Cladonia floerkeana, C. furcata and C. portentosa. The lichens were exposed to three types of powdered fertilizer (NPK-, N-, P-fertilizer) and lime. The applied nutrients were recorded in lichen thalli and soil. The influence on lichen growth rate and vegetation cover was estimated over 2 years. The response was a clear change in vegetation cover with an exceptional stimulating effect of NPK on the moss Polytrichum formosum. A lethal effect was observed on Cladonia floerkeana following exposure to lime. NPK and P had the most significant stimulatory effect on C. furcata. Only NPK promoted the growth of C. portentosa and P, N or Ca had a negative effect.
Bacidia Neosquamulosa, a new and Rapidly Spreading Corticolous Lichen Species from Western Europe
Authors: Aptroot A. , van Herk C. M. 
Published: September 2002

AbstractBacidia neosquamulosa Aptroot & van Herk, a new corticolous lichen species, is described from the Netherlands, where it seems to be rapidly spreading and where it is considered to be a neophytic species. It is also reported from Belgium and Great Britain. It resembles corticolous morphs of the rather variable B. arnoldiana, but differs from this and other species by the longer, conspicuously septate, filiform, curved, macroconidia, the longer ascospores and the squamuloseisidiate thallus.
Ecology of Foliicolous Lichens at the ‘Botarrama’ Trail (Costa Rica), a Neotropical Rainforest. IV. Species Associations, their Salient Features and Their Dependence on Environmental Variables
Authors: Lücking Robert 
Published: September 2002

AbstractA community ecology approach using an association of species test and a principal component analysis resulted in the recognition of two major and two minor foliicolous lichen communities in a neotropical rainforest. The major communities arc governed by microclimatic factors, one characteristic of the shady understorcy and the other confined to light gaps. The minor communities are due to subtle phorophyte preferences towards palm and dicot leaves. The shady understorey community is dominated by the families Anhoniaceae, Opegraphaceae, Tnchoihdiaceae and Pilocarpaceae, which predominantly have Phycepeltis as their phycobiont, thin thalli, abundant sexual reproduction, small ascospores produced in high numbers, and pyenidial conidiomata. The light-gap community is mainly composed of the families Gomphillaceae and Ectolechiaceae, with Trebouxia as their phycobiont, thickly crystalline or whitish, dispersed thalli, frequent asexual reproduction, large ascospores produced in low numbers, and specialized campylidia and hyphophores as conidiomata. Phycobiont, thallus structure, and the mode of reproduction are considered as adaptations to different microsites, whereas the shape and size of ascospores and conidia seem to be of less importance. The foliicolous lichen communities reflect the spatial and temporal structure of the forest, in particular the continuity of the shady understorey in comparison to the discontinuity of the light gaps. While the formation of the shady understorey community follows more deterministic patterns, the light-gap community exhibits high stochasticity.
Post-Fire Colonization of a Mediterranean Forest Stand by Epiphytic Lichens
Authors: Longán Angels , Gaya Ester , Gómez-Bolea Antonio 
Published: September 2002

AbstractThe post-fire colonization of a Quercus ilex forest by epiphytic lichens has been studied in Catalonia (NE Spain), eleven years after a fire. Specific richness and lichen biomass have been studied separately on Quercus ilex, Erica arborea, Rosmarinus officinalis. and Cistus albidus, to reveal possible differences among phorophytes in facilitating lichen establishment. Shrubs play an important role in colonization by common species whereas the stools of Quercus ilex offer a suitable substratum for rarer species. Cistus albidus, with the highest lichen diversity and 98·2% of the total biomass of macrolichens, is the most suitable phorophyte for lichen establishment.
Steinia Australis, A New Species in the Lichen Family Aphanopsidaceae
Authors: Kantvilas G. , McCarthy P. M. 
Published: September 2002

AbstractSteinia australis Kantvilas & P. M. McCarthy is described, based on a specimen from Tasmania. The new species, the second in the genus and only the third in the family Aphanopsidaceae, differs from S. geophana by its larger ascospores, well-developed exciple and scurfy, leprose thallus.
The Lichens of Rarotonga, Cook Islands, South Pacific Ocean I: Pyrenocarpous Taxa
Authors: McCarthy P. M. 
Published: September 2002

AbstractFour new pyrenocarpous lichens are described from Rarotonga, Cook Islands, South Pacific Ocean: Porina deminuta (Trichotheliaceae), Pyrenula ochraceoflava var. pacifica (Pyrenulaceae), Strigula decipiens var. divisa (Strigulaceae) and Verrucaria fortuita (Verrucariaceae). The new combinations Porina eminentior (Nyl.) P. M. McCarthy and P. exocha (Nyl.) P. M. McCarthy are made for Thelenella eminentior Nyl. (Clathroporina eminentior (Nyl.) Müll. Arg.) and Verrucaria exocha Nyl. (Clathroporina exocha (Nyl.) Müll. Arg.), respectively. Brief descriptions and additional notes are provided for 26 other taxa. The phytogeographical affinities and possible origins of the pyrenocarpous lichens of Rarotonga and Lord Howe Island are discussed.
Changes in Water Economy in Relation to Anatomical and Morphological Characteristics During Thallus Development in Parmelia Acetabulum
Authors: Fos Simón , Deltoro Vicente I. , Calatayud Ángeles , Barreno Eva 
Published: September 2002

AbstractThe influence on uptake and water loss of the structural changes experienced by Parmelia acetabulum during thallus development were investigated. Small specimens were characterized by flat lobes and a thin thallus and cortex. Large specimens appeared strongly rugose, imbricate and irregularly folded, and had a significantly thicker cortex and medulla than small thalli. Maximum water storage capacity did not differ between large and small thalli, although water retention was much higher in large thalli, presumably due to the interaction of structural characteristics and a higher boundary layer resistance. This translated into a longer duration of the period of thallus hydration in large thalli compared to small thalli. Incubation of thalli in water-vapour-saturated atmospheres induced full recovery of photosynthetic electron transport to the values before desiccation in small thalli but only induced a partial recovery in large thalli. The close correlation between photosynthetic electron transport and net photosynthesis during desiccation found in this species suggested that carbon-fixation activity could be regained to a larger extent by incubation of thalli in water vapour in small compared to large thalli. The higher ability for water vapour uptake of small thalli might allow them to efficiently use small amounts of intermittently available water or periods of high relative humidity. The significance of this differential ability to utilize water is discussed with regard to the known ecological preferences of the species.
Dispersal Patterns of Terricolous Lichens by Thallus Fragments
Authors: Heinken Thilo 
Published: September 2002

AbstractDispersal patterns from seven terricolous lichen species, with a high capacity for asexual reproduction by fragmentation (Cetraria muricata, Cladonia species), were studied in differing vegetation types in north-eastern Germany. Marked lichen thalli were fragmented by trampling. After 15 days the spread of thallus fragments was monitored. Whereas most of the fragments that were dispersed by wind remained within a 20-cm radius from the source, the maximal dispersal distance was 57 cm in a dry sand grassland and 68 cm in an open pioneer pine forest. Dispersal was negligible in a closed old-growth pine forest. Several fragmented lichen cushions were disturbed and removed by animals, and led to a maximal dispersal distance of 9·70 m. These results suggest that: (a) thallus fragments provide good short-distance dispersal in open vegetation, but are inefficient for long-distance dispersal, and (b) wind and animals are important factors for the dispersal of thallus fragments. For restoration management of man-made substrata, artificial introduction of lichen thalli is proposed.
Pcr Primers for the Amplification of Mitochondrial Small Subunit Ribosomal DNA of Lichen-forming Ascomycetes
Authors: Zoller Stefan , Scheidegger Christoph , Sperisen Christoph 
Published: September 2002

AbstractFour primers for the amplification of mitochondrial DNA of lichenforming ascomycetes are presented. The primers match the conserved regions U2, U4, and U6, respectively, of mitochondrial small subunit (SSU) ribosomal DNA (rDNA). Polymerase chain reaction using different combinations of the primers produced single amplification products from DNA of eight lichen-forming fungal species but did not amplify DNA of two axenic cultured algal species. The amplification product obtained from Lobaria pulmonaria was sequenced and the 894-bp sequence was compared with the mitochondrial SSU rDNA sequence of Podospora anserine. The two sequences revealed more than 76% identity in the conserved regions U3 to U5 demonstrating that we amplified mitochondrial DNA. The primers matching U2 and U6 yielded amplification products of 800–1000 bp depending on the species examined. The variation observed suggests that mitochondrial SSU rDNA may be useful for phylogenetic analyses of lichen-forming ascomycetes.
A Comparison of Morphological, Chemical and Molecular Characters in Some Parmelioid Genera
Authors: Crespo Ana , Gavilán Rosario , Elixt John A. , Gutiérrez Gabriel 
Published: September 2002

AbstractMorphological and chemical data from 64 genera of Parmeliaceae, including the most common genera in Europe, were analysed by means of neighbour–joining and parsimony analysis. Two presence/absence matrices were constructed, one for the 64 genera and a smaller one for the most common European genera. Probabilities were too low to allow grouping of the genera and only a few pairs of genera had a probability of >50% for both matrices. A molecular matrix (nuclear rDNA-ITS) of the most common genera in Europe was constructed and analysed by the method of maximum likelihood. These results were much more informative than the non-molecular matrix for establishing phylogenetic relationships among the genera.
Variability of Ribonuclease Activity in Lichen Thalli
Authors: de los Ríos Asunción , Ramírez Rosalía , Estévez Pilar 
Published: September 2002

AbstractRNase activity in Lasallia hispanica, Parmelia omphalodes and Cornicularia normoerica collected at different times and in different habitats, have shown variability that cannot be solely attributable to variation in habitat or season. Electromorph pattern of RNase activity in L. hispanica and C. normoerica, showed variations among different collection times; some bands are constant but other showed high variability, which could be related to physiological changes. It is also noteworthy that in both species one band is exclusively present in thalli from one of the sampling localities. This could be the result of an adaptation to this habitat and/or due to genetic differences.
Photobiont Inventory of a Lichen Community Growing on Heavy-Metal-Rich Rock
Authors: Beck Andreas 
Published: September 2002

AbstractThe photobiont inventory of a stand of the Acarosporetum sinopicae, lichen community comprising saxicolous, chalcophilous lichens, has been analysed. Investigated lichen species were Acarospora rugulosa, A. sinopica, Bellemerea diamartha, Lecanora polytropa, L. subaurea, Lecidea silacea, L. lapicida, Rhizocarpon geographicum, and Umbilicaria cylindrical. For all these lichen species this is the record of the photobionts, except for L. lapicida. The photobionts were cultured axenically and investigated using light microscopical and molecular methods (ITS-sequence analyses). Every lichen species contained only one photobiont species. All photobionts belong to Trebouxia jamesii, but two different subspecies were found with the morphological differences corresponding to molecular differences. The new subspecies T. jamesii subsp. angustilobata is described, differing from the typical T. jamesii by a crenulate chloroplast but identical to the latter taxon in respect to the pyrenoid structure in the light microscope. These results are discussed with respect to the photobiont inventory of the Physcietum adscendentis, analysed in an earlier study.
Two New Species of Micarea From South Africa
Authors: Coppins B.J. 
Published: September 2002

AbstractTwo new species of Micarea are described from South Africa: M. almbornii Coppins, on loose sandstone from Stellenbosch (Western Cape) and M. endoviolascens Coppins, on damp soil from Transvaal. A note is given on Lecidea geïna Stizenb.