Buttenschøn, R. M. & Buttenschøn, J. 1998: Population dynamics of Malus sylvestris stands in grazed and ungrazed, semi-natural grasslands and fragmented woodlands in Mols Bjerge, Denmark. — Ann. Bot Fennici 35: 233–246.
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Jauhiainen, J., Silvola, J. & Vasander, H. 1998: The effects of increased nitrogen deposition and CO2 on Sphagnum angustifolium and S. warnstorfii. — Ann. Bot Fennici 35: 247–256.
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Heinsoo, K. & Koppel, A. 1998: Minimum epidermal conductance of Norway spruce (Picea abies) needles: influence of age and shoot position in the crown. — Ann. Bot Fennici 35: 257–262.
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Harmaja, H. 1998: Rhododendron diversipilosum, comb. nov. (Ericaceae). — Ann. Bot Fennici 35: 263–264.
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Pellinen, K., Sarvela, J. & Uotila, P. 1998: Chromosome counts on the fern genus Gymnocarpium (Dryopteridaceae) from Finland. — Ann. Bot Fennici 35: 265–266.
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Ochyra, R. 1998: Schistidium halinae (Grimmiaceae, Bryopsida), a new moss species from the Antarctic. — Ann. Bot Fennici 35: 267–273.
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Thell, A. & Miao, V. 1998: Phylogenetic analysis of ITS and group I intron sequences from European and North American samples of cetrarioid lichens. — Ann. Bot Fennici 35: 275–286.
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Lizárraga, M., Illana, C. & Moreno, G. 1998: SEM studies of the Myxomycetes from the Peninsula of Baja California (Mexico), I. Arcyria to Fuligo. — Ann. Bot Fennici 35: 287–306.
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Buttenschøn, R. M. & Buttenschøn, J. 1998: Population dynamics of Malus sylvestris stands in grazed and ungrazed, semi-natural grasslands and fragmented woodlands in Mols Bjerge, Denmark. — Ann. Bot Fennici 35: 233–246.
Malus sylvestris (L.) Mill., is an important diversifying and structural element in semi-natural grasslands in parts of temperate Europe. Awareness of this has been growing in recent decades. Little, however, appears to be known about the dispersal of the species in nature. The field study reported here suggests that large domestic herbivores may be a major vector of dispersal, as well as providers of suitable seedbeds for germination. Of the close to 1 800 individual seedlings, the emergence and subsequent fates of which are recorded in this study, 98% have with certainty been spread through grazing by cattle or horses. The survival of the seedlings depends on a number of factors, e.g., the growth conditions due to the prevailing climate, light regimes at germination, nutrient availability, breaking of field-layer vegetation canopy and avoidance of excessive browsing. Some 20% of the seedlings may survive for longer periods if grazing ceases, while very few survive under continuous grazing. The study shows an inverse relationship between the survival rate and the grazing pressure in the early post-germination years, but it also indicates that germination density is directly related to grazing pressure. There appears to be a direct relationship between the stocking rate and level of grazing by cattle, indicating that Malus sylvestris may not be actively sought by the cattle for food. Accordingly, the survival expectancy of the seedlings is higher where grazing pressure is less and this may be used in a grazing strategy to establish or secure a population of Malus sylvestris by natural dispersal.
Jauhiainen, J., Silvola, J. & Vasander, H. 1998: The effects of increased nitrogen deposition and CO2 on Sphagnum angustifolium and S. warnstorfii. — Ann. Bot Fennici 35: 247–256.
The differences in response to four levels of N deposition rates 0, 10, 30 and 100 kg ha–1 a–1 and ambient CO2 concentrations 350, 700, 1000 and 2000 ppm were studied in a greenhouse with Finnish material: Sphagnum angustifolium (Russow) C. Jens., a species occurring over a wide nutrient regime, and S. warnstorfii Russow, a meso-eutrophic species. With increased N deposition rate, capitulum density, capitulum and stem dry masses per unit length increased in S. warnstorfii. Length increments differed statistically among the N treatments, but in the highest experimental N deposition rate there was no fall in S. angustifolium comparable to that found in S. warnstorfii. In both species, raised CO2 concentrations caused increasing trends in capitulum and stem dry masses as well as length increments. Dry mass production of S. angustifolium increased at raised CO2 concentrations. Interaction between the two treatments was not so clear as their individual effects.
Heinsoo, K. & Koppel, A. 1998: Minimum epidermal conductance of Norway spruce (Picea abies) needles: influence of age and shoot position in the crown. — Ann. Bot Fennici 35: 257–262.
Minimum epidermal conductance (gmin) of Picea abies (L.) H. Karst. needles was estimated for various positions and age classes. The values of gmin showed a lognormal distribution. There were no universal trends in correlation between gmin and shoot position in the crown. The values of gmin increased significantly in the course of needle ageing. All sample series displayed high variability, which may be caused by differences in stomatal closure and/or in cuticular conductance sensu stricto.
Harmaja, H. 1998: Rhododendron diversipilosum, comb. nov. (Ericaceae)
Harri Harmaja. — Ann. Bot Fennici 35: 263–264.
The essentially Japanese taxon Ledum palustre L. var. diversipilosum Nakai (Ericaceae) deserves the specific rank. Following the current generic concept, the taxon is at the same time transferred to the genus Rhododendron L. as Rhododendron diversipilosum (Nakai) Harmaja.
Pellinen, K., Sarvala, J. & Uotila, P. 1998: Chromosome counts on the fern genus Gymnocarpium (Dryopteridaceae) from Finland. — Ann. Bot Fennici 35: 265–266.
Chromosome counts are published for Gymnocarpium continentale (Petrov) Pojark. (n = 80), G. dryopteris (L.) Newman (n = 80), G. continentale x dryopteris (n = 80) and G. robertianum (Hoffm.) Newman (n = 80).
Ochyra, R. 1998: Schistidium halinae (Grimmiaceae, Bryopsida), a new moss species from the Antarctic. — Ann. Bot Fennici 35: 267–273.
Schistidium halinae Ochyra (Grimmiaceae, Bryopsida) is described as a new species based on ten collections from the maritime West Antarctic. It differs from the congeners in (1) its piliferous upper leaves giving the plants a hoary appearance, (2) sharply spinulose-denticulate, hyaline, broad, flattened and membraneous hair-points, 0.2–1.0 mm long on the upper leaves, (3) narrowly recurved and partially bistratose margins in the upper half leaf, (4) presence of a large central strand, (5) short-rectangular and sinuose laminal cells in the lower middle, and (6) long-rectangular basal juxtacostal cells with straight incrassate walls and quadrate to short-rectangular basal marginal cells forming a band 4–6 cells wide. Additionally, the capsules are deeply immersed in the ovate perichaetial leaves with a plane or narrowly recurved margin on one side below the apex and terminated with a long, hyaline hair-point (0.6–1.4 mm). The exothecial cells are mostly isodiametric to oblong, thin-walled with distinct corner thickenings and the peristome teeth are erect, lanceolate, perforate to irregularly cracked. The new species is fully described and illustrated and its affinities are discussed. Schistidium halinae is currently known from King George and Livingston Islands in the South Shetland Islands and from Vega and James Ross Islands near Trinity Peninsula on the NE coast of the Antarctic Peninsula. The distribution is mapped.
Thell, A. & Miao, V. 1998: Phylogenetic analysis of ITS and group I intron sequences from European and North American samples of cetrarioid lichens. — Ann. Bot Fennici 35: 275–286.
Phylogenetic analyses were carried out on 23 samples representing 10 cetrarioid taxa from Europe and North America, representing 10 cetrarioid taxa; they were compared in parsimony analyses. The study is focused on ITS sequences of the ribosomal DNA. Intervening sequences, most likely representing group I introns, were found in four taxa. The results from the phylogenetic analysis are congruent with species delimitations derived from morphological characters, regardless of the geographic origin of the material. ITS and group I intron sequences from populations within the same species usually differ at very few base positions. The inclusion of Cetraria aculeata (Schreb.) Fr. in Cetraria Ach. and the exclusion of Melanelia hepatizon (Ach.) A. Thell, Tuckermannopsis chlorophylla (Willd.) Hale, and the genera Cetrelia W. L. Culb. & C. F. Culb., Flavocetraria Kärnefelt & A. Thell, and Platismatia W. L. Culb. & C. F. Culb. from Cetraria is supported by the analyses, if the genus Vulpicida J.-E. Mattsson and M. J. Lai is maintained in this grouping.
Lizárraga, M., Illana, C. & Moreno, G. 1998: SEM studies of the Myxomycetes from the Peninsula of Baja California (Mexico), I. Arcyria to Fuligo. — Ann. Bot Fennici 35: 287–306.
In two papers, of which this is the first, the authors present a macro- and microscopic study of 45 Myxomycetes collected on the Peninsula of Baja California, Mexico. This part treats 24 species, in alphabetical order, from Arcyria affinis Rostaf. to Fuligo septica (L.) F. H.Wigg. SEM photographs of spores and capillitial threads are provided. The following taxa are reported as new to Mexico: Arcyria affinis Rostaf., A. minuta Buchet, Craterium scyphoides (Cooke & Balf) Lizárraga, Illana & G. Moreno, and Dictydiaethalium plumbeum var. cinnabarinum (Berk. & Br.) Shirai & Hara. We propose the following new combination: Craterium scyphoides (Cooke & Balf) Lizárraga, Illana & G. Moreno.