Showing papers in "Nordic Journal of Botany in 1997"
TL;DR: Like most studies of perennial grasslands, there was no close correspondence between species distribution in the vegetation and in the seed bank, and seedling recruitment was generally enhanced by disturbance.
Abstract: We examined recruitment patterns in semi-natural pastures and their relationships to disturbance and species composition at different spatial scales (0.01 m2 up to 4 m2) of both the vegetation and the seed bank. Possible associations between seedling recruitment and phenology were also studied. The study was performed in four pastures with different management history. Seedling recruitment was generally enhanced by disturbance, with the greatest effect for small-seeded species that germinate in the autumn. The local species-pool contributed to a large extent to seedling recruitment; 83 % of the recruited species were found in the vegetation, whereas 44 % of the recruited species were found in the seed bank. There were a total of 88 species found in the vegetation at different spatial scales; 61 % were recorded at the smallest spatial scale (0.01 m2). The area sampled at this scale comprised 1.25% of the area examined, indicating a small scale structuring of diversity in the pastures. The species number in the vegetation varied between 7 and 14 for the smallest scale (0.01 m2), and between 23 and 42 for the largest scale (4 m2), in the four pastures. The species number in the seed bank was less variable. Like most studies of perennial grasslands, we found no close correspondence between species distribution in the vegetation and in the seed bank. Two of the pastures had a joint management history and exhibited a close similarity of species in the seed bank, despite that one of the pastures was abandoned already in the beginning of this century.
183 citations
TL;DR: Phylogenetic analyses of partial SSU rDNA sequences from representatives of 36 pezizales associated genera did not support recognition of Pyronemataceae, Ascodesmida-ceae, and Glaziellaceae as separate from the Otideaceae, and three main evolutionary lineages were detected within the order.
Abstract: Phylogenetic analyses of partial SSU rDNA sequences from representatives of 36 pezizales associated genera are presented, including new sequences from 28 species: Aleuria aurantiaca, Ascodesmis sphaerospora, Boudiera acanthospora, Caloscypha fulgens, Cheilymenia stercorea, Cookeina sulcipes, Desmazierella acicola, Geopyxis carbonaria, Hydnotrya tulasnei, Iodophanus carneus, Microstoma protracta, Otidea leporina, Paurocotylis pila, Peziza succosa and P vesiculosa (the type species of the family Pezizaceae and the order Pezizales), Pyronema domesticum, Pulvinula archeri, Saccobolus sp., Sarcoscypha austriaca, Sarcosoma globosum, Sarcosphaera coronaria, Scutellinia scutellata and S. torrentis, Sphaerosporella brunnea, Tarzetta catinus, Thelebolus crustaceus, Trichophaea hybrida, Trichophaeopsis bicuspis, and Wilcoxina mikolae. Two taxon and character matrices were subjected to maximum parsimony, maximum likelihood, and neighbor-joining analyses. The first matrix included 28 taxa and a full character set of 1600 bp, and the second matrix 37 taxa and a restricted set of 1053 characters. The analyses using the restricted character set generally yielded the same topology as the full character set but the resolution was reduced. Three main evolutionary lineages were detected within the order: (1) Pezizaceae and Ascobolaceae, (2) Helvellaceae, Morchellaceae, Tuberaceae, and Caloscypha (Otideaceae), and (3) Sarcoscyphaceae, Sarcosomataceae, Ascodes-midaceae, Glaziellaceae, Otideaceae and Pyronemataceae. The inferred subordinal grouping is compared to extant classification schemes of the Pezizales. Sarcosomataceae and Sarcoscyphaceae are recognized as separate monophyletic groups. The analyses did not support recognition of Pyronemataceae, Ascodesmida-ceae, and Glaziellaceae as separate from the Otideaceae. Thelebolus (Thelebolaceae) clusters with extra-pezizalean genera and does not belong to the order.
82 citations
TL;DR: Larger trees with rough bark in older stands had a more species-rich lichen flora, probably because of higher substratum area and availability of more diverse microsites.
Abstract: The lichen flora on 400 Picea abies trees (branches, trunks and trunk bases) in 100 patches of suboceanic spruce forest in Central Norway has been investigated. Relationships between occurrence of the species and a number of habitat and tree variables were analysed by detrended correspondence analysis (DCA). A total of 122 lichen species were recorded. Total species number was found to be about the same on branches and trunk bases (considerably lower on trunks), but with higher β-diversity on trunk bases. Most species could be classified as branch specialists, generalists, trunk or trunk base specialists. Among the measured habitat variables, stand age, altitude and vegetation type were found to be the most important for explaining the patterns of species distributions. Alectoria sarmentosa, Mycoblastus sanguinarius and several dry bark species on trunks, including Caliciales species, were more or less confined to old forests, while Usnea spp. were more abundant in young form. Trentepohlia-containing trunk base species like Arthonia vinosa, Dimerella pineti, Lecanactis abietina and Sclerophora coniophaea showed preference for vegetation types indicating nutrient-rich substrates. The number of branch species was highest on lower altitudes while the opposite was true for trunk species. Larger trees with rough bark in older stands had a more species-rich lichen flora, probably because of higher substratum area and availability of more diverse microsites.
46 citations
TL;DR: Putative hybrids from mixed, planted or naturalized stands of P. mugo and P. sylvestris in SW and NW Jutland, Denmark, are compared with artificial F1 and spontaneous material of the natural hybrids from the Alps and the Pyrenees.
Abstract: Hybridization among Pinus mugo and P.sylvestris is visualized in Wells' distance diagrams using either equally or differently weighted characters. Parents and hybrids are better resolved in diagrams using differently weighted characters. Putative hybrids from mixed, planted or naturalized stands of P. mugo and P. sylvestris in SW and NW Jutland, Denmark, are compared with artificial F1 and spontaneous material of P. mugo × sylvestris (P. × rhaetica) from the Alps and the Pyrenees. The natural hybrids are primary hybrids, rather than introgressants.
41 citations
TL;DR: It is suggested that distinct periphytic assemblages exist, and that cyst morphotype composition and richness varies with substrate, with a high number of heavily silicified and hooked morphotypes.
Abstract: Chrysophycean stomatocysts associated with three different periphytic substrates (wet mosses, submerged mosses and rock scrapes) were investigated from ponds on Cape Herschel (78°37'N, 74°42'W), Ellesmere Island in the Canadian High Arctic. The goal of this study was to determine whether a distinct assemblage of periphytic chrysophyte cysts existed and, if so, whether assemblage composition varied with substrate and between ponds. One hundred and thirty-seven different cyst morphotypes were observed with light microscopy from 68 periphytic samples taken from 35 ponds. Twenty-six of these cysts were new morphotypes, of which 16 were identified and described using scanning electron microscopy. Significantly more cyst types with collars and hooked projections in the collar region (i.e. ‘hooked’), and fewer unomamented morphotypes were recorded in the periphytic habitats as compared to the surface sediments. Wet moss stomatocyst assemblages were particularly distinct, with a high number of heavily silicified and hooked morphotypes. The morphotype richness was far greater in periphytic environments, with 86, 100 and 95 morphotypes observed in the wet mosses, submerged mosses and rock scrapes, respectively, as compared to only 35 types in the surface sediments of the ponds. Canonical correspondence analysis indicated that measured water chemistry did not account for the variation in the species data (paxic 1 < 0.01, 999 Monte Carlo permutations). This study suggests that distinct periphytic assemblages exist, and that cyst morphotype composition and richness varies with substrate.
37 citations
TL;DR: An evergreen, cushion-forming, circumpolar, arctic-alpine plant, Diapensia lapponica, was followed for five years, 1990–1994, at the Latnjajaure Field Station, northern Swedish Lapland.
Abstract: Growth and flowering in an evergreen, cushion-forming, circumpolar, arctic-alpine plant, Diapensia lapponica, was followed for five years, 1990–1994, at the Latnjajaure Field Station, northern Swedish Lapland. This species is unusually suitable for age determination since plants grow radially from a central point of initiation. During the study period, the radial annual radial growth of cushions averaged 0.6 mm. The species exhibited a sigmoid pattern of growth in relation to the estimated age of cushions, and at least 400–year old plant individuals are present within the study area. Plants of Diapensia become reproductive at an average age of about 18 years, and may continue to flower for centuries. Recruitment to the seedling population takes place during cold periods (sequences of cold summers), and there is a negative correlation between recruitment and mean annual temperature in the Abisko area since 1913. The oldest stock of the present population at Latnjajaure was recruited during the Little Ice Age.
36 citations
TL;DR: A study was made of the vegetation in southern Wello (Ethiopia) in relation to human impact and the environment and the cover value of vascul ...
Abstract: A study was made of the vegetation in southern Wello (Ethiopia) in relation to human impact and the environment. 65 sample plots were laid out and analysed with respect to the cover value of vascul ...
36 citations
TL;DR: Hawkmoths (Theretra capensis and Hyles lineata livornica) pollinated the orchid Bonatea speciosa at a forested site along the southern Cape coast of South Africa and hawkmoth activity was confined to a short period of 40 minutes after dusk on each evening of observation.
Abstract: Hawkmoths (Theretra capensis and Hyles lineata livornica) pollinated the orchid Bonatea speciosa at a forested site along the southern Cape coast of South Africa. The flowers of B. speciosa are strongly evening-scented and hawkmoth activity was confined to a short period of 40 minutes after dusk on each evening of observation. The pollinaria are exceptionally elongated (c. 20 mm in length) and are affixed to the eyes of the hawkmoths. Pollinaria attached to feeding hawkmoths are brushed over the long stigmatic arms which project in front of flowers. The flowers of B. speciosa have a toothlike process at the mouth of the spur which forces moths to enter the flower from either side. As a result, only one of the pollinaria is removed from the flower during a visit. The division of the flower into two functional units by the toothlike process in the spur distinguishes the floral mechanism of B. speciosa from other Habenariinae.
35 citations
TL;DR: In this article, the authors examined vascular plant species richness in 39 sites (24 habitat islands, 7 "habitat peninsulas" and 8 comparable "mainland" sites) and sampled at three scales: whole sites, meadows within sites and quadrats (4 m × 4 m) within meadows.
Abstract: The increase of island species richness with area can be explained by an increase in habitat diversity or by an equilibrium of species immigration and extinction. We examined vascular plant species richness in 39 sites (24 habitat islands, 7 ‘habitat peninsulas’ and 8 comparable ‘mainland’ sites). We sampled at three scales: whole sites, meadows within sites and quadrats (4 m × 4 m) within meadows. All sites (10–104 m2) contained natural vegetation within arable fields in eascentral Sweden. There was a strong correlation between species richness and area for whole sites and for meadows There was no correlation, however, between species richness in quadrats and site area. The difference between site and meadow results on one side and quadrat results on the other suggests that species richness increases with whole site area primarily because large sites are more diverse than smaller ones. Speciearea relationships did not differ between islands, peninsula and mainland sites. Thus, patterns of species richness on our sites were more consistent with habitat diversity than an immigratioextinction equilibrium.
32 citations
TL;DR: RAPD polymorphisms used to reveal the genetic population structure of Fomitopsis pinicola from 5 populations in southwestern Sweden with outliers in Finland and Norway revealed that multiple infections were present in a single tree and that the fungus probably infects host-trees by basidiospores, arriving via the air.
Abstract: RAPD polymorphisms were used to reveal the genetic population structure of Fomitopsis pinicola from 5 populations in southwestern Sweden with outliers in Finland and Norway. Eleven primers were used on 35 isolates. Using the Analysis of Molecular Variance (AMOVA), the total variance was divided into 3 hierarchical components: 84% within populations, 11% among regions, and 5% among populations within regions. The 3 large Swedish populations contained 95% of the variation within them. The statistical significance of these patterns was supported by permutation tests. The similarity index between all genets ranged from 0.10 to 0.72, with an average of 0.45. Genets from the same population could form more than one cluster in the neighbor-joining analysis. Some of these clusters were also supported by parsimony jack-knifing. This pattern is tentatively explained by establishment of spores from different basidiomata. The result of somatic incompatibility tests and RAPD markers were compared and this comparison indicated that compatible reactions do not necessarily imply genetic identity. Sampling from cut sections of infected trees revealed that multiple infections were present in a single tree and that the fungus probably infects host-trees by basidiospores, arriving via the air. Each somatically incompatible genet characteristically monopolized only part of a resource unit. Spore trapping showed no evidence of long distance spore dispersal, but this is probably due to the limited experiment, since the genetic analysis suggested a high rate of gene flow.
25 citations
TL;DR: The perennial genus Hystrix (Triticeae) is revised and documentation is presented of diagnostic characteristics distinguishing it from genera with which it has been confused.
Abstract: The perennial genus Hystrix (Triticeae) is revised. The genus has been treated very differently by contemporary authors, but here documentation is presented of diagnostic characteristics distinguishing it from genera with which it has been confused. Six species, one divided into three subspecies, are recognized: H. patula, H. californicus, H. duthiei ssp. duthiei, H. duthiei ssp. longearistata, H. duthiei ssp. japonica, H. komarovii, H. coreana, and H. sibirica. A key, descriptions, nomenclature, variation pattern, distribution maps, and cytogenetic data are presented.
TL;DR: A number of morphological problems are discussed, such as the derivation of tetramery, and evolutionary and developmental trends in the androecium and gynoecium.
Abstract: As a first step towards a broader floral ontogenetic study on Cornales, the flowers of four species of Hydrangeaceae (Deutzia corymbosa, Kirengeshoma palmata, Philadelphus purpurascens and Hydrangea petiolaris) were studied. In Deutzia and Kirengeshoma five sepal primordia are generally initiated, in Philadelphus only four. Sepal initiation in Kirengeshoma shows a tendency to tetramony. Deutzia has a variable sepal initiation. Petal growth was never retarded in the studied species. Initiation of the androecium in Kirengeshoma, Philadelphus and Hydrangea starts with antesepalous primary primordia, on which secondary primordia are soon formed, leading ultimately to the formation of polystaminate androecia. In Deutzia a diplostemonous androecium is formed, starting with the initiation of the antesepalous stamen primordia. Gynoecium development is similar in all species studied: on a concave floral apex, a ring meristem is initiated; it develops into a variable number of continuous carpel primordia, while the centripetally growing common margins form the septa. Initiation of the ovule primordia starts halfway up each placenta and extends in an apical, basal and lateral direction. A number of morphological problems are discussed, such as the derivation of tetramery, and evolutionary and developmental trends in the androecium and gynoecium. Kirengeshoma is well settled in Hydrangeaceae, although its exact position within the family remains uncertain. A sistergroup relationship of Hydrangeaceae with Loasaceae is supported. However, Hydrangeaceae also share features with Saxifragaceae (e.g. similar gynoecium development).
TL;DR: A morphometric study of Potentilla nivea, P unijlora, and P hookeriana, as well as the close relative of the latter, P furcata, has been carried out, and the quantitative data subjected to Canonical Discriminant Analysis.
Abstract: A morphometric study of Potentilla nivea, P unijlora, and P hookeriana, as well as the close relative of the latter, P furcata, has been carried out, and the quantitative data subjected to Canonical Discriminant Analysis. The four taxa belong to the arctic-alpine section Niveae of Potentilla, and material for the analysis was collected in Alaska, U. S. A. The a priori defined groups are based on petiole hair type, the qualitative, and only, character traditionally used to distinguish taxa within Potentilla sect. Niveae. The hair types recognized previously by taxonomists have been vaguely defined, and the intraspecific variation of other morphological characters has never been discussed. Ordination by canonical discriminant analysis was performed to characterize mean differences among species, to obtain insight into group differences, and to estimate character weights from correlations between canonical variates and original variables. The four taxa differ significantly in the canonical analysis of six quantitative characters. Leaflet length, incision depth (length of leaflet teeth), and ovule number are shown to be the most important discriminators. A key to the four taxa, taking into account the intra- vesus interspecific variation, as well as character weights, is provided.
TL;DR: Seeds with smaller seeds had lower rates of abortion than those with larger seeds, and seedling size correlated strongly with seed weight in this genus, while germination speed was favored by scarification under both dark and light conditions, and vigour index was greater in scarified than in control seeds.
Abstract: We studied seed and ovule production, predation and abortion in 14 taxa of the genus Vicia. Germination capacity, seed vigour and germination kinetics after scarification were also evaluated, as well as the influence of light on these parameters. Pod size correlated with the number and weight of viable seeds, and with the total number of ovules and the number of undeveloped ovules per pod. Species with smaller seeds had lower rates of abortion than those with larger seeds, and seedling size correlated strongly with seed weight in this genus. In most taxa seed hardness was not great, and the scarifying agent used—sulfuric acid with different times of exposure—led in some cases to 100% germination. Light conditions did not notably influence germination. Germination speed was favored by scarification under both dark and light conditions, and vigour index was greater in scarified than in control seeds. In most taxa, germination after scarification fit an exponential curve, with the exception of Vicia lutea ssp. vestita, which showed very slow velocity.
TL;DR: A total of three species with five infraspecific taxa are here proposed within the genus Secale and a key is provided to the taxa.
Abstract: Some fifteen taxa ranked as species or subspecies have generally been recognized within Secale. However, most of these seem impossible to separate on morphology alone. Based on 14 morphological characters considered of diagnostic value and scored on 44 specimens representing most of the taxa a Principal Components Analysis (PCA) was carried out. Limited correlation was found between the characters and consequently the first three principal axes account for only about 60% of the total variation. The PCA shows only a weak separation of annual and perennial taxa. Further analyses mainly of spikelet characters support merging of most of the previously accepted taxa within each of these two groups. A total of three species with five infraspecific taxa are here proposed within the genus and a key is provided to the taxa.
TL;DR: Using verified records from 1970 onwards, northern distribution boundaries in Atlantic Europe and Scandinavia are established for Gracilaria bursa-pastoris, G. multipartita and G. gracilis, and the requirements for all four species are related to their geographical boundary zones.
Abstract: Using verified records from 1970 onwards, northern distribution boundaries in Atlantic Europe and Scandinavia are established for Gracilaria bursa-pastoris, G. multipartita, G. gracilis and Gracilariopsis longissima, the last two species being distinguished for the first time in Northern Ireland, Scotland, Denmark, Germany and The Netherlands. Boundaries are shown to exist as zones (rather than lines) fluctuating in location and in time. Thermal requirements for survival and growth in G. gracilis have been determined, and the requirements for all four species are related to their geographical boundary zones.
TL;DR: Two new species are described and illustrated: B. gelatinosa and B. trangenszs and the genus Curcu-morphn is referred to Boesenbergia.
Abstract: Two new species are described and illustrated: B. gelatinosa and B. trangenszs. Two new combinations are proposed: B. loerzingii and B. phyllostachya. The genus Curcu-morphn is referred to Boesenbergia. The geographical distribution of B. longifora is discussed.
TL;DR: The breeding systems of five species of Ranunculus that co-occur in the Australian alpine region were investigated in the field and glasshouse and it is indicated that autogamous seed set due to automatic and/or possible thrips mediated intrafloral pollination may be common in all five species.
Abstract: The breeding systems of five species of Ranunculus that co-occur in the Australian alpine region were investigated in the field and glasshouse. Ranunculus muelleri, R.dissectifolius, R.graniticola, R.millanii and R.niphophilus are all facultatively xenogamous. Flowers appear to promote outcrossing by incomplete protogyny (flowers are female for 1–3 days, then bisexual for 3–10 days). Hand pollinations on plants in the field demonstrate that R.muelleri, R.graniticola, R.niphophilus and R.millanii are fully self-compatible, while R.dissectifolius is only partly self-compatible. However, low index of self-incompatibility values for R.graniticola indicate that this species may also be only partly self-compatible. Moderate levels of seed set from bagged flowers indicate that autogamous seed set due to automatic and/or possible thrips mediated intrafloral pollination may be common in all five species. Polled ovule ratios ranged from 992 to 3045 for these species of Ranunculus which are consistent with facultative xenogamy. The breeding systems of the Australian Ranunculus species in the alpine region are compared to that of other Ranunculus and examined in relation to the alpine environment.
TL;DR: Anginon, a hitherto poorly known genus of woody Apiaceae endemic to southern Africa, is revised and a formal taxonomic treatment is presented, including a key to the species, correct nomenclature, typification, descriptions and distribution maps.
Abstract: Anginon, a hitherto poorly known genus of woody Apiaceae endemic to southern Africa, is revised. Field studies over several years have shown that 12 species can be recognised, of which five are newly described: A. ternatum, A. fruticosum, A. pumilum, A. tenuior and A. intermedium. The new combination A. streyi is made to transfer Sonderina streyi to Anginon, with which it shares the woody habit and heavily cutinised outer cell walls of the fruit epidermis. A formal taxonomic treatment is presented, including a key to the species, correct nomenclature, typification, descriptions and distribution maps.
TL;DR: Six new species of the genus Zingiber from Borneo are presented, including viridiflavum, chlorobracteatum, Z. flagelliforme, Z phillippsii and Z velutinum are from Sabah and Z georgeii is from Sarawak.
Abstract: Six new species of the genus Zingiber from Borneo are presented. Z viridiflavum was collected in primary lowland forest, while Z chlorobracteatum was collected in hilly secondary forest. Both are characterized by their slender fusiform inflorescences with yellow-green bracts. Z. flagelliforme found in primary lowland forest displays a peculiar reproduction habit in its tapering leafy shoots which bend over to trail on the ground where plantlets produced in the leaf-axis take root. Z velutinum was found in mid-elevation secondary forest. It is a tall plant with large ovate inflorescences and bright red, densely hairy bracts. Z phillippsii was found in a gulley in montane primary forest. It is vegetatively characterized by its purple stems and glabrous leaves while the inflorescence has a similarity to the common Bornean species Z. coloratum. Z. georgeii is distinct by its procumbent inflorescences with orange bracts. Z viridiflavum, Z. chlorobracteatum, Z. flagelliforme, Z. phillippsii and Z velutinum are from Sabah and Z georgeii is from Sarawak.
TL;DR: Nectaries of 3 1 taxa belonging to 4 subgenera of the genus Fritillaria are investigated by scanning electron and light microscopy and it is concluded that data on nectary morphology support the latest classification of the species into sub genera and informal groups.
Abstract: Nectaries of 3 1 taxa belonging to 4 subgenera of the genus Fritillaria are investigated by scanning electron and light microscopy. In most of the material investigated nectary cells were smaller and narrower, and less irregular in shape than those of the neighbouring tissue of the tepals. Species belonging to subgenus Rhinopetalum clearly differ from all other species. Their nectaries are deeply impressed, and the slit-like nectary orifice is bordered by two lobes, at least in the lower part densely hairy. In F. gibbosa, E karelinii and F. ariana, the flowers are ± zygomorphic as the nectary on the upper tepal is more deeply depressed than the others, and the nectary lobes are rather broad and fringed. In E stenanthera and E bucharica, nectaries are equally impressed in all tepals and the nectary orifice is bordered by narrow, unfringed ridges. The unique structure of nectaries in all species of this subgenus supports its separation from Fritillaria into a separate genus (Rhinopetalum Fisch. ex Alexand.). In the other subgenera, the nectaries are less impressed, often ± flattish, and usually linear to lanceolate or ovate, except in subgenus Petzlium where they are ± circular. One complex in subgenus Fritillaria is markedly distinguished from the rest of the subgenus: in the F. crassifolia group, the nectaries consist of a long and linear raised ridge with a median furrow. F. crassifolia ssp. poluninii is raised to specific level, E poluninii (fix) Bakhshi Khaniki & K. Persson, stat. nov. It is concluded that data on nectary morphology support the latest classification of the genus Fritillaria into subgenera and informal groups.
TL;DR: SEM studies of roots and rhizomes of Triglochin and Maundia of Juncaginaceae and the sole species of Scheuchzeriaceae reveals that vessels are present not only in roots, as previously reported, but also in rhizome, suggesting a close relationship between the two families often claimed.
Abstract: SEM studies of roots and rhizomes of Triglochin (one species) and Maundia (monotypic) of Juncaginaceae and the sole species of Scheuchzeriaceae, Scheuchzeria palustris, reveals that vessels are present not only in roots, as previously reported, but also in rhizomes. The perforations contain pit membranes with pores of various sizes. Striate pit membranes, like those previously seen in Acorus, occur on pit remnants in peforations and on pit membranes of lateral walls in all genera studied. Grooves interconnecting pit apertures are illustrated for root tracheary elements of Triglochin; this is believed to be a first report of this feature for monocotyledons. The tracheary elements of Juncaginaceae and Scheuchzeriaceae are similar in their thick walls and narrow slitlike pits, lending support to the close relationship between the two families often claimed.
TL;DR: The low variation in taxonomic key characters and chromosome numbers suggest that the tetraploid cytotype of S.gigantea has became naturalized in Europe, probably the result of only few introductions of this species to Europe.
Abstract: The exotic perennial Solidago gigantea belongs to the most widespread and abundant plant invaders in Europe, found throughout the range from northern Italy to southern Scandinavia. Morphological variation of this species in Europe was assessed by scoring plants from 22 populations along a north-south transect for quantitative and qualitative characters. All size related and floral characters varied significantly among populations. Size related characters exhibited large coefficients of variation and high intraclass correlations. Floral characters varied considerably less and showed rather narrow unimodal distributions. Pubescence of leaf main vein varied from glabrous to weakly pubescent. Leaf surfaces beneath as well as secondary veins were uniformly glabrous among the shoots. The first three principal components accounted for 56.5% of the variation and formed no separated clusters among the shoots sampled. Chromosome counts revealed only tetraploid cytotypes (2n=36). The low variation in taxonomic key characters and chromosome numbers suggest that the tetraploid cytotype of S.gigantea has became naturalized in Europe, probably the result of only few introductions of this species to Europe.
TL;DR: The genus Trivalvaria is distinguished from other Asian Annonaceae by the characteristic venation of the leaves, the imbricate sepals and petals, and the single basal ovule.
Abstract: The number of species in Trivalvaria is reduced from eight to four. A new variety of T. macrophylla from North Sumatra is described. Two Polyalthia species, P. nemoralis and P. oligogyna, found in Laos, North Vietnam, and Hainan, are brought into the synonymy of Z dubia. The genus further ranges from NE India and the Andarnan Islands to Java and Borneo. It is distinguished from other Asian Annonaceae by the characteristic venation of the leaves, the imbricate sepals and petals, and the single basal ovule.
TL;DR: The morphometric and isozyme data suggest that P jemtlandica has originated several times, but there is no indication of frequent or recent hybridization where the species coccur today.
Abstract: Morphometric and isozyme data were used to test the hypothesis that the pseudoviviparous Poa jemtlandica has originated as a hybrid between the sexual P flexuosa and the facultative apomict P alpina. Plants were sampled from three localities in southern Norway. In addition, some Icelandic plants were included. Both morphometric and isozyme data clearly support the hybrid hypothesis. Poa jemtlandica was morphologically intermediate between its supposed parents in several individual characters as well as in a discriminant analysis. Seven enzyme systems were analysed. Eight areas of activity were interpreted as “loci”, each of which certainly represented several duplicated genes in these plants which all are polyploid. A total of 27 different multilocus phenotypes was observed: ten phenotypes in P alpina var. vivipara, eight phenotypes in I. alpina var. alpina, seven phenotypes in P jemtlandica, and three phenotypes in P flexuosa. The phenotype of Icelandic P jemtlandica was identical to that of P. jemtlandica from one of the Norwegian localities. Additive electrophoretic patterns were observed for P jemtlandica at four individual “loci”. At the remaining “loci” some phenotypes of P. jemtlandica were most similar to P. flexuosa, others to P alpina. The data also suggest that P jemtlandica has originated several times, but there is no indication of frequent or recent hybridization where the species coccur today.
TL;DR: Cyanophytes dominated the phytoplankton of shallow Lake Mikri Prespa during the period May 1990 to September 1992 and tended to increase at temperatures higher than 16 °C and at inorganic nitrogen concentrations lower than 100 μg 1--1.
Abstract: Cyanophytes dominated the phytoplankton of shallow Lake Mikri Prespa during the period May 1990 to September 1992 (76.5 and 52.0% of the total phytoplankton biomass in 1990–1991 and 1991–1992, respectively). Biomass peaks were observed in autumn (from 5.2 to 34.5 g m-3) when low dissolved inorganic nitrogen, high phosphate phosphorus and low Zcu to Zmix ratio prevailed. The dominant species were Microcystis aeruginosa and M. wesenbergii. These represented 64 and 86% of the cyanophyte biomass in 1990–1991 and 1991–1992, respectively and revealed similar patterns of seasonality forming biomass peaks in late summer - autumn. Small chroococcalean cyanophytes (< 2 μm) showed also similar temporal distributions. Of the filamentous cyanophytes, the most important species was Anabaena lemmermannii var. minor which formed peaks in late summer and autumn (2.6 and 1.1 g m-3 in 1990 and 1992, respectively). Rainfall and the N:P ratio were probably the main factors influencing the seasonality of all of the filamentous cyanophytes in the lake. Cyanophytes, tended to increase at temperatures higher than 16 °C and at inorganic nitrogen concentrations lower than 100 μg 1--1. The frequent mixing of the water column did not seem to prohibit the substantial increase of the group.
TL;DR: The interpretation of character evolution within the genus and a first hypothesis of phylogenetic relationships, showing three distinct infrageneric groups, is presented.
Abstract: The variation in habit and morphology of the twelve species of Anginon, a poorly known southern African genus of woody Apiaceae, is discussed and illustrated. The genus Glia is shown to be the obvious outgroup, sharing with Anginon two convincing synapomorphies: 1, the reduction or partial reduction of the laminar part of the leaves, and 2, the heavily cutinized outer walls of the fruit epidermis. Several characters of the internal structure of the fruit, together with other morphological characters, have been analysed by the cladistic method. Our interpretation of character evolution within the genus and a first hypothesis of phylogenetic relationships, showing three distinct infrageneric groups, is presented.
TL;DR: Thirty-four species are recognized in this revision of Ladenbergia, but several more are represented in herbaria by material that is too incomplete for formal description.
Abstract: Ladenbergia is a neotropical genus of the tribe Cinchoneae. It is recognized by the combination of septicidal capsules, usually large, winged seeds, heterostylous flowers, presence of terminal inflorescence, and distally ridged corolla lobes. Although widely distributed in tropical Central and South America, it is heavily centered in the Andes. It is hypothesized that the ancestral area was in the premontane zone of the central Andes. Thirty-four species are recognized in this revision, but several more are represented in herbaria by material that is too incomplete for formal description. Seven species are described as new: L. dwyeri, L. nuhigena (Panama); L. klugii (Peru); L. lehmanniana, L. magdalenae, L. obovata, and L. pauccflora (Colombia). A key to the species is given, the new species are described, and distribution maps are provided for all species.
TL;DR: Several patterns of long-distance in vitro sexual compatibility are demonstrated for Agaricales and distribution and systematics of Pleurotopsis longinqua are discussed.
Abstract: Several patterns of long-distance in vitro sexual compatibility are demonstrated for Agaricales: 1) pan-Caribbean distributions of Favolus tenuiculus and Dictyopanus pusillus; 2) overland North American distribution of Phyllotopsis nidulans; 3) Gondwana-land distribution of Conchomyces bursaeformis; and 4) trans-Atlantic boreal forest distribution of Marasmius epiphyllus and Mycena rosella. Distribution and systematics of Pleurotopsis longinqua are discussed.
TL;DR: A cladistic analysis demonstrates that Brunonia australis may constitute a separate, monotypic family or alternatively be deeply nested within Goodeniaceae s.str.lat Brunonia shares a number of potential synapomorphies with Asteraceae.
Abstract: The relationships between Asteraceae, Calyceraceae, Goodeniaceae, and Brunoniaceae are discussed, and some SEM-observations of microcharacters within the two latter families are presented. Based on morphological evidence neither Goodeniaceae s.str. nor Goodeniaceae s.lat. (i.e., incl. Brunonia) appear to be the putative sister taxon of Asteraceae. A cladistic analysis demonstrates that Brunonia australis may constitute a separate, monotypic family or alternatively be deeply nested within Goodeniaceae s.lat Brunonia shares a number of potential synapomorphies with Asteraceae. Of special interest are the peculiar hairs and feathery pappus bristles which very much resemble those found within Asteraceae subfam. Barnadesioideae. However, studies with SEM disclose that these structures rather constitute autapomorphies for the taxa in question. In conclusion, Calyceraceae remain to be the best sister candidate of the sunflower family.