Sommerfeltia - Abstracts

Hansen, A. & Sunding, P. 1985. Flora of Macaronesia. Checklist of vascular plants. 3. revised edition. - Sommerfeltia 1: 1-167. Oslo
ISBN 82-9905-276-8. ISSN 0800-6865.

A complete and up-to-date checklist of the vascular plants of Macaronesia (the Azores, the Madeira archipelago, the Salvage Islands, the Canary Islands, and the Cape Verde Islands) is given. 3.125 species belonging to 1.041 genera are listed, as are also a number of intraspecific taxa down to variety level. New combinations are proposed within the genera Cheilanthes, Pericallis and Pulicaris. A second section lists 2.250 synonyms and their presumed identity.

Keywords: Macaronesia, Azores, Madeira, Salvage Islands, Canary Islands, Cape Verde Islands, Vascular plants.

Alfred Hansen, Botanical Museum, Gothersgade 130, DK-1123 Copenhagen K, Denmark.
Per Sunding, Botanical Garden and Museum. Trondheimsveien 23B, N-0562 Oslo S, Norway.

Økland, R.H. & Bendiksen, E., 1985. The vegetation of the forest-alpine transition in the Grunningsdalen area, Telemark, S. Norway. - Sommerfeltia 2: 1-224.
ISBN 82-9905-278-8. ISSN 0800-6865.

This study is divided into two parts. The general part contains a review of theories of the nature of vegetation. It is concluded that present evidence points in the direction of species individuality and vegetational continuum as responses to continuous environmental gradients, on a regional, and mostly also on a local scale. Accordingly, a gradient approach to classification of the forest and alpine vegetation of the investigated area was designed as an alternative to traditional phytosociological classification. The importance of the concept of corresponding vegetation types in different regions is stressed. It is argued that four environmental gradients explain the major variation in Southern Norwegian forest and alpine vegetation. In the special part, the vegetation of the Grunningsdalen area is treated. Two gradients, the vertical gradient and the complex-gradient topographic moisture - snow cover, are considered sufficient to explain the major variation in forest and alpine vegetation in the area. The vegetation is classified into 16 site-types by division of the gradients into four zones (according to altitude) and four series (according to moisture - snow cover) by means of floristic criteria known to reflect particular ecological conditions. For each of the site-types a description of the vegetation and an extensive comparison with corresponding Fennoscandian vegetation is given. On the basis of results from the present study area regional variation in Southern Norwegian poor vegetation corresponding to the xeric, subxeric, and submesic series, and phytosociological classification in the forest-alpine transition are discussed. Various numerical classification and ordination methods are used in an analysis of the floristic composition of the site-types and the autecology of the species. The main phytosociological gradient in the investigated vegetation runs from dry and high altitude to wet and low altitude, most closely approaching the moisture gradient. Diversity relations are discussed. It is strongly emphasized that a hierarchic system is unable to give a consistent classification of a vegetation that must be regarded as a multidimensional network of variation along environmental gradients. Viewed in the light of the results of this study, a gradient approach to classification seems most suitable for a variety of Fennoscandian ecosystems.

Keywords: Alpine vegetation, Continuum, Diversity, Forest, Forest-alpine transition, Gradient reference frame, Norway, Numerical analysis, Regional variation, Site-types, Telemark.

Rune Halvorsen Økland* and Egil Bendiksen, Botanical Garden and Museum, Univ. of Oslo, Trondheimsveien 23B, N-0562 Oslo 5, Norway (*present address: ØKOFORSK, Norwegian agricultural Univ., Box 64, N-1432 Ås-NLH, Norway).

Halvorsen, T. & Borgen, L. 1986. The perennial Macaronesian species of Bubonium (Compositae-Inuleae). - Sommerfeltia 3: 1-103. Oslo.
ISBN 82-9905-279-8. ISSN 0800-6865.

Six perennial Macaronesian species are recognized in Bubonium J. Hill emend. Briq.: the Cape Verdian B. daltonii (Webb) T. Halvorsen, with two subspecies, ssp. daltonii and ssp. vogelii (Webb) T. Halvorsen, and B. smithii (Webb) T. Halvorsen: and the Canarian B. intermedium (DC.) T. Halvorsen & Wikl., B. graveolens (Forssk.) Maire, with two subspecies, ssp. odorum (Schousb.) Wikl. and ssp. stenophyllum (Link) T. Halvorsen, B. schultzii (Bolle) Sventenius and B. sericeum (L.f.) T. Halvorsen & Wikl. Four Mediterranean annuals are superficially treated for Macaronesia: B. aquaticum (L.) Hill, Asteriscus maritimus (L.) Less., A. hierochunticus (Michon) Wikl., and A. spinosus (L.) Sch. Bip. A key to the Macaronesian Bubonium species is provided. The chromosome number n=7 is reported for all the Bubonium species in Macaronesia; in B. graveolens ssp. odorum, B. daltonii ssp. vogelii, and B. smithii for the first time. The chromosome number n=6 is confirmed for Asteriscus maritimus. The self fertile annuals are not cross compatible with the other species. Among the predominantly self incompatible perennials internal barriers to gene exchange are weak. Only B. schultzii seems genetically isolated. Between the other perennials the crossability is complete and hybrid fertility high between species from the same archipelago, but reduced between species from different archipelagos. The present occurrence of the Canarian species B. sericeum and B. intermedium and the Cape Verdean B. daltonii and B. smithii seems relict. These frutescent endemics probably belong to an old element in the Macaronesian flora.

Keywords: Bubonium, Macaronesia, Taxonomy, Chromosome numbers, Cross compatibility, Variability.

Tore Halvorsen, Paal Bergs v. 7, N-0692 Oslo 6, Norway.
Liv Borgen, Botanical Garden and Museum, Trondheimsvn. 23B, N-0562 Oslo 5, Norway.

Gjærum, H.B. & Sunding, P. 1986. Flora of Macaronesia. Checklist of rust fungi. - Sommerfeltia 4: 1-42. Oslo.
ISBN 82-7420-000-4. ISSN 0800-6865.

This is the first checklist of rust fungi in Macaronesia (the Azores, the Madeira archipelago, the Salvage Islands, the Canary Islands, and the Cape Verde Islands). One hundred and thirty-four rust taxa are recorded, making more than four hundred rust-host combinations. Names on rust and host species used in the literature are listed, with reference to the names used in the checklist.

Keywords: Macaronesia, Azores, Madeira, Salvage Islands, Canary Islands, Cape Verde Islands, Uredinales.

Halvor B. Gjærum, Norwegian Plant Protection Institute, Division of Plant Pathology, P.O.Box 70, N-1432 ÅS-NLH, Norway.
Per Sunding, Botanical Garden and Museum, University of Oslo, Trondheimsveien 23B, N-0562 Oslo 5, Norway.

Middelborg J. & Mattsson J., 1987. Crustaceous lichenized species of the Caliciales in Norway. - Sommerfeltia 5: 1-70. Oslo.
ISBN 82-7420-001-2. ISSN 0800-6865.

Thirty-nine species are recognized in the lichen genera Calicium Pers., Chaenotheca (Th.Fr.) Th.Fr., Cyphelium Ach., Microcalicium Vain. emend. Tibell, Sclerophora Chevall., and Thelomma Massal. emend. Tibell in Norway. The genus Cybebe is reduced to synonymy with Chaenotheca, and the new combinations Chaenotheca gracilenta (Ach.) Mattsson & Middelborg and Sclerophora coniophaea (Norm.) Mattsson & Middelborg are proposed. Three families are recognized, the Caliciaceae, the Coniocybaceae, and the Microcaliciaceae. The chemistry is described, and a number of unidentified secondary substances are characterized by their Rf values. The ecology and distribution of the species are described. Keys are given to the genera and species, and distribution maps for Norway are provided. Calicium adaequatum Nyl., Calicium adspersum Pers., Calicium corynellum Ach., Calicium parvum Tibell, Chaenotheca carthusiae (Harm.) Lett., and Microcalicium ahlneri Tibell are reported new to Norway.

Keywords: Caliciales, Distribution, Ecology, Lichens, Lichen substances, Norway, Taxonomy.

Jørn Middelborg & Johan Mattsson, Botanical Garden and Museum, University of Oslo, Trondheimsveien 23B, N-0562 Oslo 5, Norway.

Derrick, L.N., Jermy, A.C. & Paul, A.M. 1987. Checklist of European Pteridophytes. - Sommerfeltia 6: 1-94. Oslo.
ISBN 82-74-002-0. ISSN 0800-6865.

This is the first comprehensive checklist of European pteridophytes produced from the computerised relational database originally set up by the European Taxonomic, Floristic and Biosystematic Documentation System. The place of publication, full synonymy and distribution of 329 accepted taxa are given. Hybrids are included with annotations on putative parentage. There is a comprehensive index to all plant names.

Keywords: Pteridophyta, Europe, checklist, distribution, new combinations, new species, Asplenium, Azolla, Cystopteris, Diphasiastrum, Dryopteris, x Dryopolystichum, Equisetum, Isoetes, Pteridium.

Lewis N. Derrick, Department of Botany, The University, Reading, England. Present address: 2O Copse View, East Preston, Littlehampton, West Sussex BN16 1AY, England.
A. Clive Jermy, Department of Botany, British Museum (Natural History), Cromwell Road, London SW7 5BD, England.
Alison M. Paul, Department of Botany, British Museum (Natural History), Cromwell Road, London SW7 5BD, England.

Malme, L., 1988. Distribution of bryophytes on Fuerteventura and Lanzarote, the Canary Islands. - Sommerfeltia 7: 1-54.
ISBN 82-7420-003-9. ISSN 0800-6865.

Forty mosses and twenty-six hepatics are reported for the first time from Fuerteventura, and fifteen mosses and nine hepatics are reported for the first time from Lanzarote, among them Gigaspermum mouretii Corb. which is new to Macaronesia. All taxa recorded so far are listed and their distribution outlined. Distribution maps are given for some of the more common species. The zonation of bryophytes is considered, and a survey of their phytogeographical affinities is given. Some ecological factors are discussed, and it is suggested that the bryophyte flora of these two islands is primarily restricted by climatic factors.

Keywords: Bryophytes, Distribution, The Canary Islands, Fuerteventura, Lanzarote.

Leif Malme, Skrabben 1C, N-0682 Oslo 6, Norway.

Økland, R.H. 1989. A phytoecological study of the mire Northern Kisselbergmosen, SE. Norway. I. Introduction, flora, vegetation, and ecological conditions. - Sommerfeltia 8: 1-172.
ISBN-82-7420-004-7. ISSN 0800-6865.

A part of the mire complex N. Kisselbergmosen, termed the special area, is subjected to a detailed investigation of hydrotopography, species distributions, and ecological conditions. Species occurrences and distributions are related to four main complex-gradients: (1) the mire expanse - mire margin gradient, (2) the nutrient gradient, (3) the gradient in depth to the water table, and (4) a peat productivity gradient. The former two are termed broad-scale, the latter fine-scale gradients.
A hydrotopographical mapping was made, including establishment of a detailed map of mire features and subfeatures, and construction of a map showing the topography of the water table. Two or three synsegments and seven catchments make up the special area. Broad-scale distributions of species were mapped in a contiguous 4x4 grid, resulting in a classification of species to nine D-groups. Six zones reflecting variation along gradients (1) and (2) were discerned. The concepts of mineral soil water limit and fen plant limit were discussed by reference to hydrotopography, species distributions, and chemical composition of peat along transects.
Fine-scale patterns were studied by use of 800 randomly placed plots, analyzed with respect to vegetational composition and provided with measurements of depth to the water table. Fluctuations of depth to the water table in the period 1980-82 was related to climate. Particular emphasis was put on studying parameters of the cumulative distribution functions of depth to the water table; between-year variation, interdependence, and estimation from few observations. Species were classified to seven W-groups according to relationships with the water table, and five series were considered along this gradient. The vegetation was classified into 32 site-types by a reticulate division of the ecologial space spanned by the four gradients. These site-types were described by use of 654 randomly and 765 subjectively selected plots. The site-types were compared to main types of other works, and successional relationships of site-types were inferred from observed transitions and ecological measurements. Mechanisms responsible for vegetational variation along the four gradients are thoroughly discussed.

Keywords: Bog, Depth to water table, Distribution, Fen plant limit, Gradient, Hydro-morphology, Mire, Site-type.

Rune H. Økland, Botanical Garden and Museum, University of Oslo, Trondheimsveien 23B, N-0562 Oslo 5, Norway.

Mathiassen, G. 1989. Some corticolous and lignicolous Pyrenomycetes s. lat. (Ascomycetes) on Salix in Troms, N Norway. - Sommerfeltia 9: 1-100. Oslo.
ISBN 82-7420-005-5. ISSN 0800-6865.

A total of 29 pyrenomycetous species on Salix in Troms, N Norway are treated. Two new species are described: Herpotrichiella collapsa G. Mathiassen and Lophiotrema boreale G. Mathiassen. A new combination is proposed: Platystomum curtum (Fr.) G. Mathiassen. New to Scandinavia is Glyphium schizosporum. Nine species are new to Norway: Anthostomella melanotes, Keissleriella cladophila, Lophiostoma quadrinucleatum, Lophiotrema nucula, Melanomma fuscidulum, Platystomum curtum, Rebentischia massalongii, Rhynchostoma minutum and Saccardoella transsylvanica. Eleven species are new to Troms: Amphisphaerella xylostei, Berlesiella nigerrima, Chaetosphaeria pomiformis, Cryptodiaporthe salicella, Diatrype bullata, Enchnoa infernalis, Hysterographium elongatum, Kirschsteiniothelia aethiops, Leptosphaeria hendersoniae, Lophiostoma macrostomoides and Platystomum compressum. The remaining six species have previously been reported from Troms: Arthropyrenia lapponina, Bertia moriformis var. moriformis, Cryptosphaeria subcutanea, Hypoxylon macrosporum, H. mammatum and Melanomma pulvis-pyrius.
A dichotomous key is followed by descriptions of the species in alphabetic order. The ecology and systematics of the different species are discussed, and some difficult genera are commented upon. Comments are given on the ecology and distribution of the different Salix species in Troms.

Keywords: Ascomycetes, Distribution, Ecology, Norway, Pyrenomycetes, Salix, Taxonomy, Troms.

Geir Mathiassen, Tromsø Museum, Univ. of Tromsø, N-9000 Tromsø, Norway.

Økland, T. 1990. Vegetational and ecological monitoring of boreal forests in Norway. I. Rausjømarka in Akershus county, SE Norway. - Sommerfeltia 10: 1-52. Oslo.
ISBN 82-7420-007-1. ISSN 0800-6865.

Vegetational and ecological monitoring of boreal forests in Norway was initiated in 1988, as a part of the programme "Country-wide monitoring of forest health" at Norwegian Institute of Land Inventory (NIJOS). Ten reference areas for monitoring will be established and analysed within five years; two new areas each year. Each of the monitoring areas is planned to be reanalysed every fifth year. In each monitoring area 10 macro sample plots, 50 m2 each, are selected. Within each macro sample plot 5 meso sample plots, 1 m2 each, are randomly placed and the vegetation is analysed by using frequency in subplots as measure of species abundance. Within each meso sample plot one micro sample plot (two in the first established monitoring area), 0.0625 m2 each, is analysed by the same method. In connection with each macro sample plot several environmental variables are recorded. In each macro sample plot several tree variables and variables describing the terrain are recorded. The variables are used for environmental interpretation as well as for monitoring, since known relations between vegetation and ebvironmental gradients form the basis of vegetational and environmental monitoring. Any future changes in vegetation, soil and the health of trees have to be interpreted in relation to the analysis of vegetation-environment relationships in order to identify changes due to air pollution or climatic changes.
The data from the first established monitoring area, Rausjømarka in Akershus county, are subjected to analysis in this paper. The most important vegetational and environmental gradients in the area are discussed, as well as the field methodology and the methods for data analysis to be used in integrated monitoring. The advantages of integrated monitoring of vegetation, soil and trees on the same plots are emphasized, including advantages for surveying and monitoring of species (bioindicators).

Keywords: Boreal forests, DCA, Monitoring, Norway, Norway spruce, Ordination, Permanent plots, Vegetation ecology.

Tonje Økland, Norwegian Institute of Land Inventory, Box 115, N-1430 Ås.

Økland, R.H. (ed.) 1991. Evolution in higher plants: patterns and processes. Papers and posters presented on a symposium arranged on occasion of the 175th anniversary of the Botanical Garden in Oslo, June 5-8, 1989. Sommerfeltia 11. 183 pp. Oslo.
ISBN 82-7420-009-8. ISSN 0800-6865. Contents:

K. Apelgren: Myosotis baltica - a questionable taxon

C.C. Berg: Differentiation of flowers and inflorescences of Urticales in relation to their protection against breeding insects and to pollination

R.Y. Berg: Seed dispersal relative to population structure, reproductive capacity, seed predation, and distribution in Euphorbia balsamifera (Euphorbiaceae), with a note on sclerendochory

R. von Bothmer: Evolutionary patterns in wild barleys

O. Eriksson & L. Jerling: Hierarchical selection in clonal plants

T.W.J. Gadella: Hybridization in Symphytum: pattern and process

I. Hedberg: Morphological, cytotaxonomic and evolutionary studies in Anthoxanthum odoratum L. s. lat. - a critical review

M. Hedrén: Problems in Carex jemtlandica and C. bergrothii (Cyperaceae) in Sweden.

U.-M. Hultgård: Polyploidy and differentiation in N European populations of Primula subgenus Aleuritia

B. Jonsell: Evolutionary trends among plants in the Baltic land uplift area

I. Nordal & M.M. Laane: Cytology and reproduction in Arctic Cochlearia

J.M. Olesen & E. Warncke: Morphological, phenological and biochemical differentiation in relation to gene flow in a population of Saxifraga hirculus

P. Uotila, T. Lahti, E. Kemppainen & A. Kurtto: Population biology of threatened vascular plants in Finland

Eilertsen, O. 1991. Vegetation patterns and structuring processes in coastal shell-beds at Akerøya, Hvaler, SE Norway. - Sommerfeltia 12: 1-90. Oslo.
ISBN 82-7420-012-8. ISSN 0800-6865.

The vegetation of shell-beds is studied in an island on the coast of Skagerak, SE Norway. Within this restricted area 125 sample plots, 1 m2 each, were distributed by a restricted random procedure. Frequency in subplots and percentage cover were used for estimation of species abundance. A set of 33 environmental variables was obtained from each sample plot. Ecological gradients corresponding to the main vegetational gradients are identified by means of DCA ordination results correlated with environmental data. DCA ordination results are further interpreted by use of an earlier classification of the vegetation and by application of Grime's strategy concept. The following complex gradients were recognized: (1) the primary successonal gradient, influenced by variables dependent on site age, e.g., elevation, distance from the sea, and rate of decomposition of mollusc shells, (2) the secondary successional gradient, from open meadow vegetation via open shrub vegetation to dense shrub vegetation, highly correlated with variables independent of site age, e.g. intensity of grazing, (3) the nutrient availability gradient, and (4) the soil moisture gradient. Interpretation of relations between coenoclines and environmental variables was performed by Kendall rank correlation and relationships among ecological variables analysed by PCA ordination. Direct gradient analysis by rh-DCCA is used as a supplement to DCA. The ratio between the rh-DCCA eigenvalue and of the first ordination axis and the corresponding eigenvalue of the first residual (unconstrained) axis is used to quantify the importance of each environmental variable. The performed multivariate analyses show that the successional pathways on shell-bed shores are dependent on the grazing pressure. The relative importance of the following structuring processes is discussed: (1) interspecific interactions (competition, coexistence and facilitation), (2) destabilizing factors (disturbance and fluctuations), (3) stress, and (4) chance. Ordination and association analyses show that Juniperus communis is the most important structuring species in the material. Grazing is necessary to reduce overgrowth by junipers and to maintain a high species diversity.
The field data are used for inspection of the performance of different rescaling and detrending options, available with DCA ordination. Non-linear rescaling appears to be less influenced by deviant sample plots as compared to linear rescaling, and the S.D. units of the axes produced by non-linear rescaling are considered more interpretable in terms of a unimodal model of species responses to ecological gradients. Available options for detrending by polynomials are shown to be inferior to the detrending by segments option, as polynomial detrending may impose a polynomial distortion on the point configuration in the ordination space.

Keywords: Association analyses, DCA, Detrending, Environmental gradients, Evolutionary strategies, Hybrid-CCA, Non-linear rescaling, Ordination, Patch dynamics, Succession.

Odd Eilertsen, Botanical Garden and Museum, University of Oslo, Trondheimsveien 23B, N-0562 Oslo, Norway.

Gulden, G. and Hanssen, E. W. 1992. Distribution and ecology of stipitate hydnaceous fungi in Norway, with special reference to the question of decline. Sommerfeltia 13: 1-58. Oslo.
ISBN 82-7420-014-4. ISSN 0800-6965.

Since a decline in stipitate hydnaceous fungi has been reported in some parts of Europe, their occurrence in Norway merits consideration. The present study was intended to determine whether decline has taken place in Norway, and to form a basis for future monitoring of a group of organisms which may include important bioindicators of airborne pollution.
Twenty-eight species are recognised in Norway, belonging to the genera Auriscalpium (1), Bankera (2), Hydnellum (10), Hydnum (2), Phellodon (4), and Sarcodon (9). They are most common in eastern parts of Norway, and eutrophic spruce forests are the preferred habitats. Distribution maps and information on habitat preferences for each species are provided. The species are ranged in five groups according to their distributional patterns, occurrence in vegetational regions, and distributions in other parts of Eurasia. Factors regulating the occurrence of the species are discussed for each group.
An evaluation of the frequency of the species through the decades back to 1950 is presented. There is so far no strong evidence for decline of these fungi in Norway. However, there is a statistically significant decrease in observations of the three Hydnellum species: H. aurantiacum, H. peckii, and H. suaveolens.

Keywords: Auriscalpium, Bankera, Bioindicator, Distribution, Ecology, Hydnellum, Hydnum, Monitoring, Mycorrhiza, Norway, Phellodon, Sarcodon, Stipitate Hydnaceous Fungi.

Gro Gulden, Botanical Garden and Museum, University of Oslo, Trondheimsvn. 23B, N-0562 Oslo.
Even W. Hanssen, Bjerkeset s., N-3624 Lyngdal i Numedal.

Tønsberg, T. 1992. The sorediate and isidiate, corticolous, crustose lichens in Norway. - Sommerfeltia 14: 1-331. Oslo.
ISBN 82-7420-015-2. ISSN 0800-6865.

128 species in 45 genera of sorediate and isidiate, crustose, corticolous lichens are recorded from Norway. Accounts of their morphology, chemistry, and substratum preferences are presented, and a discussion of their distribution in Norway is supported by maps for a number of taxa. With few exceptions, the taxa can be distinguished on thallus characters alone. Several taxa, especially those with brown or blue-pigmented soralia, have soredia with a distinct cortex. New species are: Buellia arborea Coppins & Tønsb. (from Norway and Scotland), Fuscidea arboricola Coppins & Tønsb. (from Norway, Sweden, and Scotland), F. pusilla Tønsb. (from Norway, Sweden, and Scotland), Lecanora flavoleprosa Tønsb. (from Norway and Austria), L. flavopunctata Tønsb. (from Norway and Sweden), L. norvegica Tønsb. (from Norway), Lecidea gyrophorica Tønsb. (syn. L. epizanthoidiza auct., non Nyl.), L. praetermissa Tønsb. (from Norway and Sweden), L. subcinnabarina Tønsb. (from Norway), L. vacciniicola Tønsb. (from Norway, Sweden, and Spain), Lecidella subviridis Tønsb. (from Norway and Sweden), Lepraria elobata Tønsb. (from Norway), L. jackii Tønsb. (from Norway), L. obtusatica Tønsb. (from Norway), L. umbricola Tønsb. (from Norway, England, and Scotland), Micarea coppinsii Tønsb. (from Norway and Scotland), Rinodina flavosoralifera Tønsb. (from Norway), R. disjuncta Sheard & Tønsb. (from Norway and the pacific coast of U.S.A. and Canada), and Schaereria corticola Muhr & Tønsb. (from Norway, Sweden and Scotland). Ochrolechia androgyna s. lat. is shown to comprise at least four distinct species.
New combinations are: Cliostomum leprosum (Räsänen) Holien & Tønsb., Lepraria rigidula (B. de Lesd.) Tønsb., Mycoblastus caesius (Coppins & P. James) Tønsb., Placynthiella dasaea (Stirton) Tønsb., and Ropalospora viridis (Tønsb.) Tønsb. Lecidea turgidula var. pulveracea Fr. is raised to specific level with the new name Lecidea leprarioides Tønsb. Mycoblastus sterilis Coppins & P. James is reduced to synonymy with M. fucatus Stirton.
Pertusaria borealis is new to Europe. Halecania viridescens, Lecanora farinaria, Lepraria caesioalba Laundon ined., L. eburnea Laundon ined., Megalospora tuberculosa, Opegrapha multipuncta, and Scoliciosporum gallurae are new to Scandinavia. Mycoblastus caesius, Lecidella elaeochroma "f. soralifera", L. flavosorediata, Micarea granulans (saxicolous, not treated), Opegrapha sorediifera, and Rinodina degeliana are new to Norway.
In some cases, Poelt's species pair concept can be applied to this group of lichens. Additional secondary substances, not occurring in the primary species, sometimes occur in the soralia of the secondary species. In this case, presence of the additional substance cannot be regarded as an independent taxonomic character, and the species pair concept is still useful. However, morphologically indistinguishable specimens with different chemistry may represent different secondary species.
The term consoredia is introduced to denote diaspores composed of aggregated soredia.

Keywords: Ascomycetes, Distribution, Isidia, Lichens, Lichen substances, Norway, Soredia, Substratum ecology, Taxonomy.

Tor Tønsberg, Botanical Institute, University of Bergen, Allégt. 41,
N-5007 Bergen, Norway.

Holtan-Hartwig, J. 1993. The lichen genus Peltigera, exclusive of the P. canina group, in Norway. - Sommerfeltia 15: 1-77. Oslo.
ISBN 82-7420-017-9. ISSN 0800-6865.

Seventeen species of the lichen genus Peltigera, exclusive of the P. canina group, are accepted from Norway. Their morphology, chemistry, ecology, and distribution in Norway are presented, and a key to the species is provided. Peltigera retifoveata is reported as new to Norway and a new species, P. sp. 1, which belongs to the P. aphthosa group, is treated but not formally described.
Different morphotypes of P. aphthosa, P. malacea, and P. neopolydactyla and different chemotypes of P. aphthosa, P. elisabethae, P. horizontalis, P. malacea, P. neopolydactyla, P. scabrosa, and P.sp. 1 are described. Correlations between several morphotypes and chemotypes are shown, but these are not treated as taxonomic units, although they probably are biological species.
Phototype pairs in P. aphthosa, P. britannica, and P. venosa are described, and the close relationship between the two first mentioned and P. malacea is pointed out.

Keywords: Chemotypes, Distribution, Ecology, Lichens, Lichen substances, Morphotypes, Norway, Peltigera, Phototype pairs, Taxonomy.

Jon Holtan-Hartwig, Botanical institute, University of Bergen, Allégt. 41, N-5007 Bergen, Norway.

Økland, R.H. & Eilertsen, O. 1993. Vegetation-environment relationships of boreal coniferous forests in the Solhomfjell area, Gjerstad, S Norway. - Sommerfeltia 16: 1-254. Oslo.
ISBN 82-7420-018-7. ISSN 0800-6865.

The understory vegetation (vascular plants, bryophytes and lichens) in an area dominated by boreal coniferous forests is subjected to detailed ecological analysis. Two hundred meso sample plots (1 m2) are used as basis for vegetation sampling, and provided with measurements of 33 environmental variables. Species abundance is recorded as frequency in 16 subplots. Parallel DCA and 2-dimensional LNMDS ordinations of meso sample plots were largely identical, both provided two coenocline axes interpretable in ecological terms. The first axis is interpreted as the response to a broad-scale topographical complex-gradient, made up of two independent complex-gradients; (1) a topography-soil depth complex-gradient in the pine forest (running from lichen-rich pine forests to submesic Vaccinium myrtillus-dominated spruce forests), and (2) a complex-gradient in soil nutrient status in the spruce forest. The second axis, mainly affecting the species composition of the bottom layer, is interpreted as a fine-scale paludification gradient. The causes of variation along these gradients are discussed: Desiccation tolerance is considered to act directly on the physiology of vascular plant species, setting their limits towards xeric sites. Similarly, cryptogams with optima in the more mesic sites are considered to be excluded from drier sites by physiological tolerance. Limits of cryptogams towards more mesic sites are, however, considered to be set by competitive ability (growth rates) in accordance with the competitive hierarchy theory. N availability is assumed to be the most important factor for differentiation of vascular plants along the nutrient gradient, while bryophytes are expected to respond to a complex of factors, including structural properties of the humus layer. Increasing N accumulation in the humus towards xeric sites may indicate oversaturation due to deposition of airborne NO3- or NH4+. Fine-scale paludification, mainly of a soligenous type, occurred in sloping terrain with shallow soil. The cryptogams apparently make up a competitive hierarchy also along the paludification gradient. No other coenoclines could be identified by analysis of 0.0625 m2 micro sample plots, most probably because the response of vegetation to micro-scale environmental gradients (probably most important: the variation in microtopography) not essentially different from the meso-scale gradients, and because the importance of random processes increase towards finer scales. Structuring processes are discussed with reference to the observed patterns. The lack of a closed bottom layer in almost all sample plots is considered a strong indication of high importance of fine-scale disturbance and density-independent mortality in the investigated system, while interspecific competition is of lower importance. The methodology in vegetation ecological studies is discussed with particular reference to monitoring. The potential of an integrated concept using permanent plots, parallel investigation of vegetation and environmental parameters, and gradient analysis, is stressed. Several suggestions for future studies, based on this integrated approach, are made.

Keywords: Boreal coniferous forests, DCA, Environmental factors, Gradient, LNMDS, Monitoring, Norway, Ordination, Vegetation.

Rune H. Økland & Odd Eilertsen, Botanical Garden and Museum, Univ. of Oslo, Trondheimsvn. 23B, N-0562 Oslo, Norway.

Hansen, A. & Sunding, P. 1993. Flora of Macaronesia. Checklist of vascular plants. 4. revised edition. - Sommerfeltia 17: 1-295. Oslo.
ISBN 82-7420-000-0. ISSN 0800-6865.

An up-to-date checklist of the vascular plants of Macaronesia (the Azores, the Madeira archipelago, the Salvage Islands, the Canary Island, and the Cape Verde Islands) is given. 3,106 species belonging to 1,062 genera are listed, as are also a number of intraspecific taxa down to variety level. 20 new nomenclatural combinations are made within the genera Atalanthus, Lavandula, Pericallis, Satureja, and Sinapidendron. A second section lists ca. 2,300 synonyms and their presumed identity.

Keywords: Macaronesia, Azores, Madeira, Salvage Islands, Canary Islands, Cape Verde Islands, Vascular plants.

Alfred Hansen, Botanical Museum, Gothersgade 130, DK-1123 Copenhagen K, Denmark.
Per Sunding, Botanical Garden and Museum, Trondheimsveien 23 B, N-0562 Oslo, Norway.

Ardévol González, J.F., Borgen, L. & Pérez de Paz, P.L. 1993. Checklist of chromosome numbers counted in Canarian vascular plants. - Sommerfeltia 18: 1-59. Oslo.
ISBN 82-7420-020-9. ISSN 0800-6865.

An up-dated checklist of chromosome numbers counted in Canarian vascular plants is presented. Reports in both endemic and naturalized species, as well as infraspecific taxa and natural hybrids, are included. Altogether, chromosome numbers are reported in 636 species of vascular plants of Canarian origin, that is in c. 30 % of the Canarian vascular flora.

Keywords: Canary Islands, Chromosome numbers, Vascular plants.

J.F. Ardévol González & P.L. Pérez de Paz, Department of Biology (Botany), University of La Laguna, E-38271 La Laguna, Tenerife, Canary Islands, Spain.
Liv Borgen, Botanical Garden and Museum, University of Oslo, Trondheimsveien 23 B, N-0562 Oslo, Norway.

Bendiksen, E., Bendiksen, K. & Brandrud, T.E. 1993. Cortinarius subgenus Myxacium section Colliniti (Agaricales) in Fennoscandia, with special emphasis on the Arctic-alpine zones. - Sommerfeltia 19: 1-37. Oslo.
ISBN 82-7420-021-7. ISSN 0800-6865.

The taxonomy and ecology of Cortinarius subgenus Myxacium section Colliniti in Fennoscandia is treated. Most species of this group have their optima in oligotrophic habitats, and play an important role in upper boreal and Arctic-alpine regions. Variation in spore morphology is subjected to numerical treatment. Relevant nomenclatural types and protologues for classical names are examined.
Presence of clamp connections is stated to be an important diagnostic character towards the most closely related section, Defibulati. Also, SEM pictures have revealed a significant difference in the spore ornamentation between the two groups. Spore shape and size provide important diagnostic characters for separation of the different taxa of section Colliniti, as shown by scattergrams. The most distinctive species in this respect are found to be C. mucosus, with characteristically narrow spores, and C. collinitus with larger spores. The species concept within the group is discussed.
Seven Fennoscandian species are recognized and their taxonomy and ecology are discussed. C. septentrionalis (type from Norway) and C. fennoscandicus (type from Finland) are described as new. Both species are common in upper (northern) boreal mountain birch (Betula) woodlands and under the low shrub Betula nana in the low alpine and arctic zones. The status of Agaricus collinitus Sow: Fries is discussed in more detail.

Keywords: Cortinarius, Myxacium, taxonomy, ecology, Arctic-alpine, Fennoscandia.

Egil Bendiksen, Norwegian Institute for Nature Research (NINA), P.O. Box 1037 Blindern, N-0315 Oslo, Norway.
Katriina Bendiksen, (formerly K. Metsänheimo), Botanical Garden and Museum, Trondheimsvn. 23 B, N-0562 Oslo, Norway.
Tor Erik Brandrud, Norwegian Institute for Water Research (NIVA), P.O. Box 69 Korsvoll, N-0808 Oslo, Norway.

Mathiassen G. 1993. Corticolous and lignicolous Pyrenomycetes s. lat. (Ascomycetes) on Salix along a mid-Scandinavian transect. - Sommerfeltia 20: 1-180. Oslo.
ISBN 82-7420-022-5. ISSN 0800-6865.

The pyrenomycete flora on Salix is examined along a mid-Scandinavian transect. A restricted number of Salix species and a fixed number of host individuals are examined in each of the vegetation regions in central Norway, and in two vegetation regions in north-central Sweden. This investigation addressed the unsolved problems listed in my previous study (Mathiassen 1989) and the same 29 taxa are treated. The following new species are described: Amphisphaerella erikssonii G. Mathiassen, Glyphium grisonense G. Mathiassen, Keissleriella holmiorum G. Mathiassen, Leptosphaeria tollens G. Mathiassen, and Saccardoella kanderana G. Mathiassen. The type material has been examined for all 29 species mentioned in the study, except Bertia moriformis var. moriformis.
A dichotomous key is followed by reviews of the species in alphabetical order. A systematic survey of the investigated taxa is also given. In addition to comments on taxonomy, ecology and distribution for the different pyrenomycete species, substrate ecology and host specificity are discussed. Statistical treatment of spore measurement data form the basis for a discussion of geographical variation. Multivariate techniques (ordination) are used to investigate the relative importance of geographic (including climatic) factors and the substrate tree.

Keywords: Ascomycetes, Distribution, Ecology, Ordination, Pyrenomycetes, Salix, Scandinavia, Taxonomy.

Geir Mathiassen, Tromsø Museum, University of Tromsø, Lars Thøringsvei 10, N-9006 Tromsø, Norway.

Rydgren, K. 1994. Low-alpine vegetation in Gutulia National Park, Engerdal, Hedmark, Norway, and its relation to the environment. - Sommerfeltia 21: 1-47.
ISBN 82-7420-026-8. ISSN 0800-6865.

A reference site for vegetational and ecological monitoring of low-alpine vegetation has been established in Gutulia National Park, Engerdal, Hedmark, Norway. Fifty vegetation plots, each 1 m2, were distributed randomly along four open transects. Species abundance was recorded as frequency in 16 subplots. Each plot was supplied with measurements of 26 environmental variables. The first axes of DCA and LNMDS ordinations were closely similar. The first DCA axis was interpreted as a complex snow cover gradient. Several environmental variables varied along this gradient, among them unevenness, soil moisture and soil nutrient status. The cover of the bottom layer varied along the complex-gradient. DCA axis 2 was interpreted as a microclimatic gradient. Partitioning of the environmental and spatial variation in species composition showed that the spatial variation in the data set was rather low. Monitoring alpine vegetation is considered important since alpine ecosystems may be particularly vulnerable to airborne pollution.

Keywords: CCA, Environmental gradients, DCA, LNMDS, Low-alpine vegetation, Monitoring, Norway, Ordination, Permanent plots, TWINSPAN, Vegetation.

Knut Rydgren, Norwegian Institute of Land Inventory, Box 115, N-1430 Ås. Present address: Division of Botany, Department of Biology, University of Oslo, P.O.Box 1045 Blindern, N-0316 Oslo, Norway.

Økland, T. 1996. Vegetation-environment relationships of boreal spruce forests in ten monitoring reference areas in Norway. - Sommerfeltia 22: 1-349.
ISBN 82-7420-028-4. ISSN 0800-6865.

Vegetational and environmental monitoring of boreal spruce forest was initiated in 1988, as a part of the programme "Contrywide Monitoring of Forest Health" at the Norwegian Institute of Land Inventory (NIJOS). As a basis for monitoring, relationships between trees, understory vegetation and environmental conditions (vertical relationships) were analysed for each of ten reference areas. The reference areas were selected to span regional gradients, in climatic conditions and deposition of airborne pollutants, in old-growth, so-called "bilberry- dominated", "small-fern" and "low-herb", also paludified, spruce forests south of the Polar Circle. Fifty 1-m2 meso sample plots, randomly chosen within ten 50-m2 macro sample plots in each reference area, were subjected to vegetation analysis, using frequency in subplots as species abundance measure. Environmental (including soil chemical) and tree parameters were recorded for meso as well as macro sample plots.

The main vegetational gradients were found by parallel use of DCA and LNMDS ordination methods and subjected to environmental interpretation, mainly by means of non-parametric correlation analyses. DCA and LNMDS in most cases revealed the same main gradients in vegetation, but outliers were more frequent in LNMDS ordinations, due to higher vulnerability of this method to plots with deviating number of species. A complex-gradient in nutrient conditions, with pH and the concentration of nitrogen as the most constantly contributing variables, but with considerable between-area variation with respect to important cations, was evident in nine reference areas. Soil moisture varied along the second vegetational gradient in most areas. In the three most humid reference areas, the Ca concentration was related to variation in soil moisture and gradients from below to between trees, while unrelated or inversely related to the same vegetational gradient as pH. Species abundances were plotted on plot positions in DCA ordinations in order to summarize the speciesï responses to environmental variation in each area.

Variation in vegetation in the total data set (500 meso sample plots) was partitioned onto two sets of explantory variables (environmental and climatic/geographical) by use of CCA, in order to find the relative importance of environmental and climatic/geographical variation. The fraction of variation exclusively explained by environmental variables was about 17%, while only 5% of the variation was explained exclusively by climatic variables. The variation shared by both sets of variables was about 8%.

The main vegetational gradients and environmental/climatic/geographical complex-gradients in the total data set were found by DCA and subsequent interpretation of axes. The main complex- gradients found by separate analyses of data from each reference area, were reflected along the DCA axes in total ordinations, but differences between areas with respect to positions along both environmental and climatic/geographical gradients were also evident.

Meso plot occurrences of selected species were plotted in a DCA ordination of the total data set, with variation exclusively due to climatic/geographical variables removed, in order to express regional similarities and differences in the speciesï responses to the environment. The different patterns of speciesï distributions in the DCA ordination were discussed in the light of their use as indicators of specified environmental conditions.

Keywords: Boreal spruce forest, CCA, DCA, Ecology, Environment, Gradient, LNMDS, Monitoring, Norway, Ordination, Permanent plots, Vegetation.

Tonje Økland, Norwegian Institute of Land Inventory, Box 115, N-1430 Ås, Norway.

Tønsberg, T., Gauslaa, Y., Haugan, R., Holien, H. & Timdal, E. 1996. The threatened macrolichens of Norway - 1995. - Sommerfeltia 23: 1-258.
ISBN 82-7420-029-2. ISSN 0800-6865.

On request from The Directorate for Nature Management (DN), Trondheim, a revised red list for Norwegian macrolichens is presented. The present list supersedes the preliminary list published by Direktoratet for naturforvaltning (1992) and includes 69 species of the currently known c. 430 species of macrolichens in Norway. The compiling of the list is mainly based on studies of relevant herbarium material in all major Fennoscandian herbaria of all species believed to be rare or endangered in Norway and on field work carried out on the localities in 1992þ1994. Of 1938 known localities for threatened macrolichens in Norway, 1046 were investigated. Collema coccophorum and Leptogium britannicum are classified as extinct (Ex), 16 species as endangered (E), 11 as vulnerable (V), 9 as in need of monitoring (V+), 18 as rare (R), 5 as indeterminate (I), and 7 as insufficiently known (K). Parmeliopsis esorediata is assigned to category A (special responsibility). Special maps summarize the distribution of all species within each of the categories E, V, V+, and R. Norway has European responsibility for 18 species and Fennoscandian responsibility for 55 species of macrolichens. Among the species included in the red list, Norway has the only or the main population for several species on a Fennoscandian (55 species), European (18), or world-wide basis (1).

Each species is described and discussed with respect to substrate and habitat preferences, threats, and status in Norway. For species known from more than five localities, maps indicate the status in each locality. A complete locality list is given for each species. Distributions in Fennoscandia, Europe and on a world-wide basis are briefly reviewed. Recommendations are given for conservation purposes.

Threatened macrolichens are concentrated in deciduous forests and woodlands along the southwestern coast, old-growth spruce forests in central Norway, and old-growth boreal forests and agricultural landscapes in eastern Norway.

Keywords: Air pollution, Biodiversity, Conservation, Forestry, Landuse changes, Lichens, Norway, Protection, Red list, Threats.

Tor Tønsberg, Botanical institute, University of Bergen, Allégt. 41, N-5007 Bergen, Norway.
Yngvar Gauslaa, Department of Biology and Nature Conservation, Agricultural University of Norway, P.O. Box 14, N-1432 Ås, Norway.
Reidar Haugan and Einar Timdal, University of Oslo, Botanical Garden and Museum, Trondheimsveien 23B, N-0562 Oslo, Norway.
Håkon Holien, University of Trondheim, Museum of Natural History and Archaeology, Department of Botany, N-7004 Trondheim, Norway.

Brochmann, C., Rustan, Ø.H., Lobin, W. & Kilian, N. 1997. The endemic vascular plants of the Cape Verde Islands, W. Africa. - Sommerfeltia 24: 1-356. Oslo.
ISBN 82-7420-033-0. ISSN 0800-6865.

The archipelago of Cape Verde consists of nine main islands of oceanic origin situated 500 km west of the African mainland. The present study aims at incleasing our knowledge of the endemic vascular flora and it origin and evolution, and at providing a scientific basis for its protection. One endemic genus (Tornabenea) and 82 endemic species and subspecies were accepted, including one new species in Tornabenea (T. humilis) and three new combinations in Campylanthus and Kickxia. Morphological descriptions, illustrations, typifications, chromosome numbers, phyto- and ecogeographic information, and conservation status, based on field-, herbarium-, garden-, and literary studies, are provided. The degree of endemism was 10.5% at the species level. The endemic flora had a mixture of holarctic (65%, including 15% in a NW-Moroccan element) and tropic (35%) affinities. Thirty-three Capeverdean endemics (40%) were most closely related to taxa with a Canaro-Madeiran distribution. The endemic flora was divided into five distributional elements (northern, western, southern, eastern, and ubiquitous; with 26, 21, 15, 3, and 17 taxa, respectively) and three ecological elements (hygrophytic, mesophytic, and xerophytic; with 31, 34, and 17 taxa, respectively). Although distributional patterns corresponded closely to geographic positions of island groups, the patterns could be sufficiently explained by ecological factors. Endemic species richness was strongly correlated with humidity and maximum island altitude. The tropic proportion decreased with increasing altitude and humidity. More than half of the endemic flora is presently threatened (Red List taxa), and 16 single-island extinctions were recorded.
The proportion of polyploids was 27% based on 63% of the endemics, which is similar to the proportion in the endemic Canarian flora. Most taxa (90%) were schizoendemic diploids or mesopolyploids, typically differentiated ecogeographically among islands and along humidity gradients. This pattern has frequently been complicated by parallel inter-island evolution along similar gradients, and many ecogeographically ubiquitous mesophytes showed large and complex interpopulational variation. In such cases, differentiation alone continuous, steep, and tree-less coast-mountain gradients of humidity has resulted in eco-morphological clines of populations rather than classic adaptive radiation into distinct taxa.
Contrary to previous beliefs, we suggest that the present Capeverdean flora is very young, possibly only a few hundred thousand years old. It contains no palaeoendemics in the strict sense, only a single endemic genus, and most endemic taxa are only slightly differentiated morphologically from their sister groups. This conclusion is supported by recent geological, palaeontological, and molecular data. A possible scenario with origins and extinctions of successive Capeverdean floras is outlined, following the dramatic fluctuations between wet and dry climates in northern Africa during the Quaternary. The present flora was probably founded by two main waves of immigrants, both via dispersal from (north-)western Africa, but in different climatic periods.

Keywords: Cape Verde Islands, Taxonomy, Endemism, Conservation, Island evolution, Ecogeography.

Christian Brochmann and Øyvind H. Rustan, Botanical Garden and Museum, University of Oslo, Trondheimsveien 23B, N-0562 Oslo, Norway.
Wolfram Lobin, Botanisches Institut und Botanischer Garten, Rheinische Friedrich-Wilhelms-Universität Bonn, Meckenheimer Allee 171, D-53115 Bonn, Germany.
Norbert Kilian, Botanischer Garten und Botanisches Museum Berlin-Dahlem, Königin-Luise-Strasse 6-8, D-14191 Berlin, Germany.

Skrindo, A. & Økland, R.H. 1998. Fertilization effects and vegetation-environment relationships in a boreal pine forest in Åmli, S Norway. - Sommerfeltia 25: 1-90. Oslo.
ISBN 82-74200-0-5. ISSN 0800-6865.

Species composition in 144 sample plots, each 1 m2, in 35-year old pine forest in Åmli municipality in Aust-Agder, S Norway, was recorded. The plots were systematically placed within the 12 blocks in a factorial fertilization experiment [addition of nitrogen (2 levels), magnesium and phosphorus], initiated six years before our analysis was carried out. At each sample plot, 28 explanatory variables were recorded. Results obtained by parallel use of three ordination methods demonstrated existence of one main coenocline from lichen-rich sites to sites rich in mosses and ericaceous species. The coenocline was interpreted by analysis of correlations between plot positions and explanatory variables, and by analysis of spatial structure using geostatistical methods, as a fine-scale moisture complex-gradient. Important correlated variables were: humus depth, tree density and canopy closure, and microtopography. Small, but significant effects of fertilization by nitrogen and phosphorus on the vegetation was demonstrated and discussed.

Keywords: Boreal pine forest, CCA, DCA, Ecology, Environment, Fertilization, Gradient, LNMDS, Magnesium, Nitrogen, Norway, Ordination, PCA, Phosphorus, Vegetation.

Astrid Skrindo, Botanical Garden and Museum, Univ. of Oslo, Trondheimsvn. 23B, N-0562 Oslo, Norway. Present address: Department of Horticulture and Crop science, Agricultural Univ. of Oslo, P.O. Box 5022, N-1432 Ås, Norway.

Rune Halvorsen Økland, Botanical Garden and Museum, Univ. of Oslo, Trondheimsvn. 23B, N-0562 Oslo, Norway.

Granmo, A. 1999. Morphotaxonomy and chorology of the genus Hypoxylon (Xylariaceae) in Norway. - Sommerfeltia 26: 1-81. Oslo.
ISBN 82-74200-0-037-3. ISSN 0800-6865.

The Norwegian species of Hypoxylon have been treated with respect to their ecology, morphology and taxonomy. Their host trees have been identified and percentage frequency of each host and substrate type (bark/wood) calculated. Ecologically the species are grouped according to their saprobic ability, and to their preferred hosts and substrates (bark or wood). From a chorological point of view the species are grouped into three different geoelements according to the distributional centre for each species in Norway, thereby also taking into consideration the total Nordic distribution. Complete locality lists for each species are given and a key to all Nordic species is presented.
Twelve species of Hypoxylon have so far been recognized in Norway: Hypoxylon cercidicola, H. cohaerens, H. fragiforme, H. fuscum, H. howeianum, H. laschii, H. macrosporum, H. multiforme, H. porphyreum, H. rubiginosum, H. salicicola and H. vogesiacum. Two species belong to Hypoxylon sect. Annulata: Hypoxylon cohaerens and Hypoxylon multiforme, the remainder belong to Hypoxylon sect. Hypoxylon. Two new species are described: H. porphyreum and H. salicicola. In a previous treatment of Nordic species of Biscogniauxia and Hypoxylon, Hypoxylon cercidicola and H. salicicola were included in and reported as H. rubiginosum and H. rutilum, respectively, while H. porphyreum was included in H. fuscum. Hypoxylon macrosporum and H. laschii, by several authors considered as varieties of H. vogesiacum and H. rubiginosum, respectively, are treated as species.

Keywords: Ascomycota, chorology, distribution, ecology, Hypoxylon, morphology, Norway, taxonomy, Xylariaceae.

Alfred Granmo, Tromsø Museum, University of Tromsø, N-9037 Tromsø. Norway (e-mail: alfredg@imv.uit.no)

Granmo, A., Læssøe, T. & Schumacher, T. 1999. The genus Nemania s.l. (Xylariaceae) in Norden. - Sommerfeltia 27: 1-96. Oslo.
ISBN 82-74200-0-038-1.ISSN 0800-6865.

A taxonomic study of Nemania Gray, Entoleuca Syd. and Euepixylon Füisting (= Nemania s.l.; Xylariaceae) was carried out for the Nordic countries: Norway, Sweden, Finland and Denmark. No species of Nemania have been found in the remaining Norden: Iceland and the Faeroes. Fourteen species of Nemania s. str. were found in the area: Nemania aenea, N. aureolutea comb. n., N. atropurpurea, N. carbonacea, N. chestersii, N. colliculosa comb. n., N. confluens, N. diffusa, N. effusa, N. prava n. sp., N. reticulata comb. n., N. serpens, and two unknown species (Nemania spp. A and B) not formally described because of scanty material. In addition the two split-outs from Nemania, Entoleuca mammata and Euepixylon udum, are treated. A dichotomous key has been prepared and the species are reviewed alphabetically with comments on taxonomy, ecology and chorology. All species have been drawn, photographed and mapped. In addition to conventional taxonomic procedures, a selection of species from Nemania s.l., Biscogniauxia and Hypoxylon were subjected to an ITS nrDNA sequencing study. This study supported the delimitation of taxa as defined in this work, and confirms Nemania as different from Hypoxylon and Biscogniauxia. Four European Nemania taxa are still unknown in Norden: Nemania gwyneddii (Whalley, R.L. Edwards & S.M. Francis) Pouzar, N. illita (Schwein.) Pouzar, Nemania serpens (Pers.: Fr.) Gray var. macrospora (J.H. Mill.) Pouzar. The fourth taxon, Hypoxylon terricola J.H. Mill. certainly also belongs to Nemania.

Keywords: Ascomycota, chorology, ecology, Entoleuca, Euepixylon, Hypoxylon, key, molecular study, morphology, Nemania, Norden, Nordic countries, phylogeny, taxonomy, Xylariaceae.

Alfred Granmo, Tromsø Museum, University of Tromsø, N-9037 Tromsø. Norway (e-mail: alfredg@imv.uit.no).

Thomas Læssøe, Department of Mycology, Botanical Institute, Copenhagen University Øster Farimagsgade 2D, DK-1353 Copenhagen K, Denmark.

Trond Schumacher, Division of Botany and Plant Physiology, Department of Biology, University of Oslo, P.O. Box 1045 Blindern, 0316 Oslo, Norway.

Krog, H. 2000. Corticolous macrolichens of low montane rainforests and moist woodlands of eastern Tanzania. - Sommerfeltia 28: 1-75. Oslo.
ISBN 82-7420-0-041-1. ISSN 0800-6865.

A total of 224 species of corticolous macrolichens are recorded from low montane rainforests and moist woodlands in the West Usambara Mountains, the Nguru Mountains, the Uzungwa Mountains, the Poroto Mountains, and the Rungwe volcano in eastern Tanzania. Local distribution data are provided. The new species Hypotrachyna olivetorica Krog, Parmotrema iringense Krog, and Ramalina dissimilis Krog are described. Heterodermia dissecta, H. fragilissima, Parmelinopsis expallida, and Phyllopsora kiiensis are reported as new to Africa. Cetrariastrum africanum, Pannaria santessonii, Parmotrema degelianum, P. fragilescens, P. hicksii, P. iringense, P. laciniatulum, Ramalina dissimilis, R. pocsii, and Usnea antiqua are at present known only from eastern Tanzania. Some of them may possibly belong to an endemic element in the montane lichen flora of the country. Hypotrachyna olivetorica, Lobaria holstiana, Phyllopsora africana, P. dolichospora, and P. mauritiana are known only from eastern Tanzania and the Mascarenes.

Keywords: Lichens, rainforests, endemism, Tanzania, the Mascarenes.

Hildur Krog, Botanical Garden and Museum, University of Oslo, Trondheimsveien 23 B, N-0562 Oslo, Norway.

Økland, R.H., Økland, T. & Rydgren, K. 2001. Vegetation-environment relationships of boreal spruce swamp forests in Østmarka Nature Reserve, SE Norway. - Sommerfeltia 29: 1-190. Oslo.
ISBN 82-7420-043-8. ISSN 0800-6865.

Swamp forests dominated by Picea abies contribute strongly to the total plant species richness in boreal forests. The variation in species composition and environmental conditions in swamp forests and the relationships of swamp forests to mires and upland forest, have, however, remained insufficiently known. From a preliminary survey of 57 spruce swamp forests, eleven localities were selected to represent the variation in the study area with respect to size and nutrient status, and altitude and position in the landscape. Physiographic and hydrotopographic descriptions were made. A total of 150 1-m2 plots were distributed on the localities by a restricted random procedure. In each plot, the abundance of all vascular plants, bryophytes and macrolichens was recorded as frequency in 16 subplots, 53 variables (topographic and geographic, tree influence, water-table, water chemical and physical, and soil chemical and physical) were measured. The gradient (coenocline) structure of vegetation was found by parallel DCA and LNMDS ordinations, interpreted ecologically by analysis of correlations and geostatistical patterns. The two main coenoclines were the same for the full species composition and for vascular plant and cryptogams considered separately. The first gradient was related to soil acidity and nutrient concentrations: plots segregated into relatively poor (and intermediate) and richer swamp forests. Nitrogen availability is considered a decisive factor for species' responses to this gradient. The second gradient was related to depth to the water table and mesotopographic relief of the swamp-forest surface, varying mostly on fine (0.75-1.5 m) scales. Vascular plants segregate along this gradient due to a trade-off between tolerances to waterlogging and drought, bryophyte are influenced by a complex set of factors. Two minor vegetation gradients were also found; one related to microtopography (extending from flat, lawn-like areas dominated by large bryophytes to more strongly sloping sites dominated by small mosses and hepatics; 'pocket species') and one weakly related to the annual water-table amplitude. Relatively strong coenoclines were found that separated entire swamp forests but were uncorrelated with measured variables. These occurred because all swamp forests, notably the richer, had a strong element of uniqueness in species composition, probably because species are recruited from a large species pool during thousands of years. Swamp forest is proposed as a broad term for all peatlands with trees, including mire margin, from which it is essentially indistinguishable. Similarities with, and differences from, open mire and forest on mineral soil are discussed. Some unique features of swamp forests are pointed out. A classification of swamp forests into eight site-types by division of the two main gradients is proposed. Descriptions are provided for the six site-types encountered in the study area. All intact richer swamp forests and a representative selection of poor swamp forests should be protected if maintenance of the biological diversity of (coniferous) forests in general, and swamp forests in particular, is aimed at.

Keywords: Boreal coniferous forests, DCA, Environmental factors, Gradient, LNMDS, Norway, Ordination, Swamp forest, Vegetation.

Rune H. Økland, Botanical Museum, Univ. of Oslo, Sars' gt. 1, N-0562 Oslo, Norway and Norwegian Institute of Land Inventory, P.O. Box 115, N-1430 Ås, Norway;
Tonje Økland, Norwegian Institute of Land Inventory P.O. Box 115, N-1430 Ås, Norway
Knut Rydgren, Department of Biology, Division of Botany and Plant Physiology, University of Oslo, P.O. Box 1045, Blindern, N-0316 Oslo, Norway and Norwegian Institute of Land Inventory (present address: Sogn og Fjordane College, P.O. Box 133, N-6851 Sogndal, Norway).

Bendiksen, E., Økland, R.H., Høiland, K., Eilertsen, O. & Bakkestuen, V. 2004. Relationships between macrofungi, plants and environmental factors in boreal coniferous forests in the Solhomfjell area, Gjerstad, S Norway. - Sommerfeltia 30: 1-125. Oslo.
ISBN 82-7420-044-6. ISSN 0800-6865.

The macrofungal species composition and its relationships to ecological factors and vegetation were investigated in a boreal coniferous forest area. Macrofungi were recorded in 99 16-m2 macroplots, each divided into 16 subplots of 1 m2. Presence/absence of each species was recorded in every subplot and frequency in 16 subplots was used as abundance measure. Two 1-m2 plots within each macro plot had previously been analysed with respect to vascular plants, bryophytes and macrolichens. All plots were provided with measurements of 36 environmental variables. Parallel DCA and two-dimensional LNMDS ordinations of macroplots identified the same two coenocline axes. One more coenocline axis identified by DCA was also possible to interpret ecologically. The first fungal coenocline corresponded to the main coenocline for vegetation, comprising the variation from pine to spruce dominated forests; from ridge via slope to valley bottom. This coenocline is interpreted as the response to two independent complex-gradients: (1) a topography-soil depth complex-gradient in the pine forest, and (2) a complex-gradient in soil nutrient status in the spruce forest. While macro-scale topographic variables were relatively more strongly correlated with the vegetational coenocline, soil pH and nitrogen content were more strongly correlated with the fungal coenocline. It is argued that the soil moisture deficiency hypothesis, i.e. that species differ in drought tolerance, proposed as an explanation for variation along the main vegetational coenocline in pine forests, also applies to pine-forest macrofungi. The responses of macrofungi and plants to edaphic conditions in spruce forest were found to differ in one important respect: while plants common on poor soils are normally present also in richer sites, many macrofungal species were absent or rare there. Reasons for this are discussed. The second coenocline (only identified by DCA), only relevant for the spruce forest, reflected the variation from bryophilous fungal species that avoided sites with dense deciduous litter to saprotrophic species living on incompletely decayed Populus and Betula litter and ectomycorrhizal fungi associated with deciduous trees. The third coenocline strongly correlated with median soil moisture and also related to fine-scale canopy closure was interpreted as due to a fine-scale paludification gradient. The correspondence between ordination results obtained for fungi and plants demonstrates (1) that distributional patterns of macrofungi and plants within forests to a large extent (but not completely) are caused by the same major environmental complex-gradients and (2) that the same field and analytical methods are applicable to both groups of organisms.

Keywords: Boreal coniferous forests, DCA, Environmental factors, Fungi, Gradient, LNMDS, Macromycetes, Mycorrhiza, Norway, Ordination.

Egil Bendiksen and Vegar Bakkestuen, Norwegian Institute for Nature Research, P.O. Box 736 Sentrum, N-0105 Oslo, Norway
Rune H. Økland, Botanical Museum, Univ. of Oslo, P.O. Box 1172 Blindern, N-0318 Oslo, Norway, and Norwegian Institute of Land Inventory, P.O. Box 115, N-1430 Ås, Norway
Klaus Høiland, Department of Biology, Division of Botany and Plant Physiology, University of Oslo, P.O. Box 1045 Blindern, N-0316 Oslo, Norway
Odd Eilertsen, Norwegian Institute for Nature Research (present address: Norwegian Institute of Land Inventory)

Økland, R.H. 1990. Vegetation ecology: theory, methods and applications with reference to Fennoscandia. - Sommerfeltia Supplement 1: 1-233. Oslo.
ISBN 82-7420-006-3. ISSN 0802-8478.

This textbook presents the conceptual basis for modern vegetation science. The gradient nature of vegetation and the environment is emphasized. Variation in species abundance along environmental complex-gradients is described, and species response models discussed. Advantages of using gradients scaled in units of compositional turnover for the study of species resposes are given. The classical continuum controversy in vegetation ecology is reviewed. The niche concept is also reviewed, with reference to gradient theory. The theoretical part concludes with an overview of processes structuring vegetation (interspecific interactions, destabilizing factors, stress and chance), and their relevance to major Fennoscandian ecosystems are discussed.
Major approaches to description of Fennoscandian vegetation, the Braun-Blanquet approach and the Northern traditions (the Uppsala school of phytosociology and the Finnish site-type approach), are reviewed. The applicability of phytosociological methods in a multidimensional continuum is discussed.
Methods in vegetation ecology are reviewed, with particular emphasis on techniques for gradient analysis. The phases of vegetation ecological studies are treated in the order: sampling, pre-processing of data (data manipulation), and gradient analysis. Sampling designs are reviewed and discussed with emphasis on suitability for different research purposes. The conflict between homogeneity and representativity of plots and its consequences for plot size is discussed. Species abundances measures are compared. Matrix models in vegetation ecology are described. The main types of data manipulation operations for vegetation data, weighting and standardization, are explained. Floristic dissimilarity measures are reviewed, and the conceptual shortcomings of all floristic dissimilarity measures as measures of ecological distance is emphasized.
Gradient analysis includes four types of techniques that assist interpretation of species-gradient relationships: regression and calibration (univariate approaches; one response variable), and ordination and constrained ordination (multivariate techniques; many response variables). The roles of these four types in gradient analysis are explained, with particular emphasis on ordination. The rationale of ordination is explained statistically and geometrically. Ordination methods that can be interpreted statistically may be explained as a process of recurrent regressions and calibrations. The most important ordination techniqies, PCA, CA, DCA and LNMDS are described in detail, their faults explained and their relative suitability for use with data sets with specified properties thoroughly discussed. No ordination method exists that never produces distorted or artifactual axes, but guidelines are given for the identification of such axes. Constrained ordination is explained and the relationship of this family of techniques to ordination briefly commented on.
Numerical classification techniques are briefly discussed in the concluding chapter.

Rune Halvorsen Økland, Botanical Garden and Museum, University of Oslo, Trondheimsveien 23B, N-0562 Oslo 5, Norway.

Økland, R.H. 1990. Studies in SE Fennoscandian mires, with special regard to the use of multivariate techniques and the problem of scaling ecological gradients. - Sommerfeltia Supplement 2: 1-22. Oslo.
ISBN 82-7420-010-1. ISSN 0802-8478.

The study presents the results from an integrated approach to hydromorphology, species distribution, and ecological conditions in SE Fennoscandian bogs and poor fens. Patterns of distribution are observed on spatial scales ranging from 0.25 m2 to whole mires (1 km2), and the scope of the study extended to include the regional perspective. Detailed ecological studies studies are performed within a restricted part (0.3 km2) of one mire complex, N. Kisselbergmosen, Rødenes, SE Norway, while the distribution of plant species and hydromorphological mire types is studied within parts (1000 km2) of Akershus and Østfold counties, SE Norway. Patterns are interpreted by use of multivariate techniques, in particular ordination by detrended correspondence analysis (DCA). On the scale of one mire, four complex-gradients are shown to account for most of the vegetational variation. The relative merits of different sampling procedures and classification systems are discussed. On a broader scale, gradient relationships of vegetation, hydromorphology and species distributions can mostly be ascribed to variation in thermal and hygric factors, often operating in conjunction. Their effects on the vegetation are often mediated by differential water supply. Structuring factors in boreal mires are discussed, and interspecfic interaction as well as abiotic factors are important. The importance of interactions is higher in the bottom layer in the field layer. On a fine scale, boreal mires are considered to conform to the patch dynamics theory of non-equilibrium coexistence of species. On a broad scale, boreal mires appear to be in a dynamic equilibrium with present climatic conditions east of the limit for the onset of erosion. The common conceptual basis for descriptive biogeography and vegetation ecology is emphasized. Arguments in favour of scaling ecological gradients in units of compositional turnover are forwarded, and the properties of one such scaling method, the nonlinear rescaling procedure in DCA ordination, is outlined. The advantage of an integrated approach to ecological problems is emphasized.

Keywords: Bog, DCA, Fennoscandia, Gradient scaling, Hydromorphology, Mire, Phytogeography, Vegetation.

Rune Halvorsen Økland, Botanical Garden and Museum, University of Oslo, Trondheimsveien 23B, N-0562 Oslo 5, Norway.

Hestmark, G. 1991. To Sex, or not to Sex...Structures and Strategies of Reproduction in the Family Umbilicariaceae (Lecanorales, Ascomycetes). - Sommerfeltia Supplement 3: 1-47. Oslo.
ISBN 82-7420-013-6. ISSN 0802-8478.

This is a study of the evolution and ecology of reproduction in the family of lichen-forming fungi Umbilicariaceae comprising the two genera Umbilicaria and Lasallia. Members of this family exhibit a variety of reproductive structures and strategies. The fungal partner of the symbiosis may reproduce by sexually generated ascospores, asexual thalloconidia, or both. Propagules reproducing the intact symbiosis include asexual isidia, soredia, thallyls, phyllidia and schizidia. The algal partner - unicellular Pseudotrebouxia (Chlorophyceae) - reproduces by asexual autospores when in symbiosis, and in addition zoospores and aplanospores in pure culture.
In about half of the species in Umbilicariaceae the fungal partner can only reproduce sexually - it is exclusively teleomorphic. In these species, apparently, the option of asexual reproduction has not been presented by evolution. In the taxa where this option has been presented, the forces of ecology and evolution seem to favour this option. Although no taxon with asexual reproduction appears to have dispensed with sexuality altogether, the allocation to sexual reproduction tends to decrease and the resources are translocated to asexual reproduction. Different taxa represent progressive stages in this de-evolution of sex. In some of these cases sex is correlated with geographical distribution patterns or ecological factors such as high humidity or high population density and sib-competition. The latter observation supports the 'Tangled Bank' hypothesis for the maintenance of sex, as well as ESS models for reproductive allocations in heterocarpic plants. In some cases exclusively teleomorphic taxa co-exist with morphologically virtually identical but mainly asexual (anamorphic) taxa, suggesting that a difference in reproductive mode may have led to speciation.
Associated with different propagule types are a number of other traits with consequences for the ecological performance of the species. These sets of correlated traits constitute strategies of reproduction, the core sets of specific life-history strategies. Three 'pure' reproductive strategies are tentatively distinguished in the Umbilicariaceae, depending on whether the propagule is sexually or asexually generated and whether it is symbiotic or not. The asexual propagules are close-dispersed while sexual propagules are more far-dispersed. A comparative study of the performance of representatives of the three strategy types in two glacier forelands shows that the sexually reproducing species are the fastest colonizers. The need to re-establish symbiosis at target site appears to be no great obstacle to sexual reproduction by ascospores.

Keywords: Asexual reproduction, ESS, Evolutionary ecology, Lasallia, Lichen-forming fungi, Reproduction, Sex, Tangled Bank, Thalloconidia, Umbilicaria.

Geir Hestmark, Botanical Garden and Museum, University of Oslo, Trondheimsveien 23B, N-0562 Oslo 5, Norway.

Brochmann, C. 1992. Polyploid evolution in arctic-alpine Draba (Brassicaceae). - Sommerfeltia Supplement 4: 1-37. Oslo.
ISBN 82-7420-016-0. ISSN 0802-8478.

The mainly arctic-alpine genus Draba is well known for its complex morphological and chromosomal variation. This paper reviews a larger study of Nordic Draba, aimed to provide insights into evolutionary processes that confound taxonomic relationships in the genus. The populations analyzed were referred to 16 currently recognized species of the sections Draba (petals white), Chrysodraba (petals yellow), and Drabella (petals yellow), and investigated using enzyme electrophoresis, restriction site analysis of cpDNA and rDNA, and analysis of chromosome numbers, artificial and natural hybrids, reproductive biology, habitat differentiation, and morphology.
Section Draba comprises three diploids and seven polyploids (4x-10x) based on x = 8, sect. Chrysodraba comprises five polyploids (4x-16x) based on x = 8, and sect. Drabella comprises D. crassifolia, which probably is octoploid based on x = 5. Artificial F1 hybrids were obtained in 19 interspecific combinations. Later-generation hybrids were obtained in seven of these combinations. The genetic data suggest that 1) all polyploids are genetic allopolyploids, i.e., they show disomic inheritance and are highly fixed-heterozygous; 2) several of the polyploids have originated recurrently, some of them even polyphyletically; 3) some of the alloploid populations may have originated from cross-incompatible, sibling species that all belong to a single diploid taxonomic species; 4) interspecific gene flow across chromosome number barriers is possible and probably occurs in natural situations; 5) each of three of the polyploids represents an independent alloploid lineage, whereas sect. Draba and two species of sect. Chrysodraba form an intricate phylogenetic network; 6) some of the polyploids have originated locally, others have migrated repeatedly into the Nordic area; and 7) the phenotypic expression of genes encoding taxonomically important morphological characters does not follow consistent patterns in hybrids; this result may explain the discrepancies between genetic and taxonomic relationships in this highly reticulate genus.
All species are sexual autogams, but there was large variation in autogamous seed set and traits promoting cross-pollination. The diploids are genetically depauperate, extremely inbreeding stress-tolerators occupying restricted ecological niches, whereas most of the polyploids have high levels of genetic variation, occupy a wide range of niches, and are either stress-tolerant competitors with a mixed mating system or primarily inbreeding ruderals. Mixed mating appears advantageous in the polyploids occurring in competitive habitats, although their fixed heterozygosity buffers the effect of selfing with respect to loss of variability. The ecological amplitude, heterozygosity, and biochemical diversity in the species were positively correlated and increased significantly with ploidal level. Two hypotheses are advanced to explain these correlations: 1) the general-purpose genotype hypothesis, which suggests that a high level of fixed heterozygosity in an allopolyploid genotype per se allows for exploitation of several different niches; and 2) the special-purpose genotype hypothesis, which suggests that repeated alloploidizations involving genetically divergent progenitors result in different fixed-heterozygous genotypes, each of which may exploit a particular niche.
The evidence for multiple polyploid origins, differentiation into sibling diploids, and interploidal gene flow in Draba add to a growing data base suggesting that polyploid complexes represent considerably more dynamic genetic systems than previously envisioned. In Draba, the principal evolutionary importance of these processes is probably that they serve as escapes from genetic and ecological depauperation caused by uniparental inbreeding at the diploid level. These processes inevitably result, however, in incongruities between taxonomic and evolutionary entities in the genus, supporting the use of a wide species concept.

Keywords: Enzyme electrophoresis, DNA restriction site analysis, Crossing experiments, Polyploidy, Fixed heterozygosity, Multiple origins, Gene flow, Breeding systems, Ecological amplitude, Draba.

Christian Brochmann, Botanical Garden and Museum, University of Oslo, Trondheimsveien 23B, N-0562 Oslo, Norway.

Hansen, A. & Sunding, P. 1994. Botanical bibliography of the Canary Islands. Bibilografía botánica de las Islas Canarias. - Sommerfeltia Supplement 5: 1-116. Oslo.
ISBN 82-7420-023-3. ISSN 0802-8478.

An up-to-date bibliography of botanical literature related to the Canary Islands is presented, listing 2,378 titles covering all disciplines of botany. Titles dealing with phytochemical or agricultural aspects may, however, be incomplete.

Resumen en español: Se presenta una bibiliografía botánica al día de las Islas Canarias, con 2,378 títulos que cubren las disciplinas de la botanica. Sin embargo, los títulos que tratan de aspectos phytoquímicos o agrícolas som probablemente incompletos.

Keywords: Canary Islands, Macaronesia, botanical literature, bibliography.

Alfred Hansen, Botanical Museum, Gothersgade 130, DK-1123 Copenhagen K, Denmark.
Per Sunding, Botanical Garden and Museum, Trondheimsveien 23 B, N-0562 Oslo, Norway.

Økland, R.H. 1995. Boreal coniferous forest vegetation in the Solhomfjell area, S Norway: structure, dynamics and change, with particular reference to effects of long distance airborne pollution. - Sommerfeltia Supplement 6: 1-33. Oslo.
ISBN 82-7420-027-6. ISSN 0802-8478.

Seventeen original papers that are parts of, or spin-offs from, the TVLF project "Effects of long distance airborne pollution", are summarized. All papers include data from the Solhomfjell reference area, a S Norwegian old-growth boreal coniferous forest with high deposition of long distance airborne pollution relative to other parts of Norway. Vegetation and environmental structure, population and vegetation dynamics, and vegetation change, was integrated by extensive use of the same sample sets. The nested sampling included 100 extended macro sample plots (64 m2) for tree species and 200 meso sample plots for the understory (1 m2; with 33 environmental variables measured and presence/absence of all species recorded in 16 subplots). Species abundances were recorded in 50 meso plots all years 1988-93, while all 200 plots were analyzed in 1988 and 1993. Other sampling designs were used for three special studies in the Solhomfjell area. Population biology of Hylocomium splendens was studied in six of NIJOS' ten areas for vegetational and environmental monitoring of Norwegian boreal spruce forests, as well as in the Solhomfjell area.
Gradient relationships of vegetation at the 1 m2 scale in the Solhomfjell area are summarized by DCA ordination. Three coenoclines are identified: (1) a broad-scale gradient from xeric, lichen-dominated pine forest via subxeric pine forest dominated by ericaceous species and poor, Vaccinium myrtillus-dominated spruce forest to richer, herb-rich spruce forest, (2) a fine-scale gradient in degree of paludification (e.g., dominance by Sphagnum spp.), most strongly visible in the bottom layer, and (3) a micro-scale gradient from dominance by small hepatics and mosses to dominance by larger mosses of the forest floor. Associated complex-gradients were identified or hypothesized by use of measured environmental variables: (1) danger of soil moisture deficiency and soil nutrient content, (2) median soil moisture, and (3) several aspects of microtopography. Several kinds of independent evidence indicates that physiological tolerance is more important than interspecific competition in the understory. Temporal variation in soil moisture and soil pH is studied, with reference to the main gradients. Persistence of cryptogams as well as vascular plant species was species-specific and size-dependent, with little variation between years. The rate of vegetation dynamics varied predictably along the main coenocline, in relation to site productivity and environmental harshness. The magnitudes of one-year change in species abundances and vegetation were used to evaluate the significance of change in the five-year period. Significant humus acidification occurred in the five-year period, most strongly in richer spruce forest where several vascular plant species declined and vegetation changed in direction of poor spruce forest. N fertilization may explain the increase of Deschampsia flexuosa in spruce forest. Significant enrichment of pine forest humus is demonstrated. Norway spruce and Scots pine showed inconsistent patterns of variation in relative crown density. Stem number and stand volume in permanent plots increased for all tree species.
Modular growth, branching patterns, and hence demography of the clonal moss Hylocomium splendens, was strongly size-dependent. Branching increased and risk of termination decreased with increasing segment size. Strong apical dominance was found. A combination of positive density-dependence of mean segment size, and regulation of segment numbers at very high densities was demonstrated. Mean segment size was strongly related to length of the photosynthetically active period. Increase of most bryophytes in the Solhomfjell area 1988-93 was primarily due to several mild, rainy winters during the period.
Advantages of an integrated approach to monitoring of boreal forests (including trees, understory and environment; the population, species and vegetation levels of organization; several spatial and temporal scales; and univariate as well as multivariate statistical methods) are emphasized. Data from other regions and longer time periods are needed to assess the extent of vegetation response to environmental change.

Keywords: Acidification, Coniferous forest, DCA, Dynamics, Environmental change, Gradient, Hylocomium splendens, Scale, Vegetation.

Rune Halvorsen Økland, Botanical Garden and Museum, University of Oslo, Trondheimsveien 23B, N-0562 Oslo 5, Norway.

Rydgren, K. 1997. Fine-scale disturbance in an old-growth boreal forest - patterns and processes. - Sommerfeltia Supplement 7: 1-25. Oslo.
ISBN 82-7420-030-6. ISSN 0802-8478.

This is a study of the importance of fine-scale disturbance on the forest floor in a bilberry dominated old-growth Norway spruce forest in Akershus county, Norway. Propagule banks and the impacts of experimental disturbance are studied on vegetation and population levels of organization. All studies were carried out within a framework of gradients in vegetation that are interpreted ecologically, by means of three different ordination techniques and univariate statistical methods. The relative merit of the ordination techniques in summarizing structure in the present data set is discussed. The first ordination axis was interpreted as due to a complex-gradient in soil moisture (decreasing) and canopy closure (increasing). Since the performance of plant individuals (or modules) in part depends upon the abiotic environment, it is argued that an approach that integrates studies at the vegetation and population levels will be beneficial to the studies at both levels and, notably, that such an integrated approach will enhance the explanatory power of population studies. It is stressed that ordination technique must be chosen after careful consideration of data set properties.

The importance of performing experimental field studies is emphasized. Such studies are important in order to allow testing of hypotheses. Patterns, processes and rates of recovery following fine-scale disturbance are discussed. In the disturbance experiment species number rapidly (within 2-3 years) reached pre-disturbance levels or higher, while the rate of recovery was much slower for the vegetation cover, in particular of the bottom layer. The relative efficiencies of the three main revegetation processes, i.e. germination from the propagule bank, colonization, and clonal encroachment, are shown to depend on disturbance severity, areal extent and distance of dispersal. Species with numerous viable diaspores in the soil-buried propagule bank may have an advantage over other species in revegetation of disturbed patches by just being present. However, soil condition and climate constrain germination and growth, making some species microsite limited.

New insights into the pattern, processes and rate of recovery of the clonal moss Hylocomium splendens, have been gained from the studies of experimental disturbance. This species is demonstrated to have a remarkable ability to rapidly increase its population size through enhanced branching after fine-scale disturbance. The implication of these results is that very little can be deduced about the history of a population on the basis of a snapshot of branching rates, when the disturbance history of the site is unknown.

Keywords: Boreal forest, Bryophyte, Disturbance, Field experiment, Gap, Gradient, Hylocomium splendens, Propagule bank, Recovery.

Knut Rydgren, Department of Biology, Division of Botany and Plant Physiology, University of Oslo, PO Box 1045 Blindern, N-0316 Oslo, Norway

Publisert 4. mai. 2010 15:39