bluuebunny/crossref_metadata_2025 huggingface dataset:
CFD Modeling of a Thermal and Shear-Thinning Elastohydrodynamic Line Contact
Authors: Hartinger Markus , Dumont Marie-Laure , Ioannides Stathis , Gosman David , Spikes Hugh
Published: August 2008

In this paper a computational fluid dynamics (CFD) approach for solving elastohydrodynamic lubrication using the freely available package OPENFOAM is introduced. The full Navier–Stokes equations are solved, which enables the entire flow domain to be modeled and all gradients inside the lubricated contact to be resolved. The phenomenon of cavitation is taken into account by employing a homogenous equilibrium cavitation model, which maintains a specified cavitation pressure inside the cavitating region. The energy equation used considers the effects of heat conduction and convection, viscous heating, and the heat of evaporation. The developed method has been applied to a series of cases of lubricated metal-on-metal line contact with an entrainment velocity of uent=2.5m∕s, viscosities η0=[0.01,1]Pas, and slide-to-roll ratios SRR=[0,1,2] under both thermal and isothermal conditions. The isothermal results are compared to the Reynolds theory and most results agree very well. Only the high-viscosity pure rolling case shows small differences. The combined effects of temperature, pressure, and shear-thinning are studied for the thermal cases. A temperature-induced shear band occurs in the case of sliding combined with very large viscosity compared to the isothermal case, which results in significant pressure variations across the thickness of the film. The impact of temperature on the friction force is discussed, showing differences of up to −88.5% compared to the isothermal case. The developed method is capable of giving new insights into the physics of elastohydrodynamic lubrication, especially in cases where the usual assumptions of the Reynolds theory break down.
Quantitative Analysis of Cavitation Erosion Particle Morphology in Dilute Emulsions
Authors: Abouel-Kasem A. , Saleh B. , Ahmed S. M.
Published: August 2008

Wear particles produced by vibratory cavitation erosion tests on 1017 carbon steels in water and oil-in-water (o∕w) emulsions were analyzed. Scanning electron microscope (SEM) images of wear particles were acquired, forming a database for further analysis. The particle morphology features were first clarified. Next, the size parameters (size, area, and perimeter) and shape factors (elongation and roundness) were determined for each test liquid, using image analysis software. The size parameters of the removed particles were higher in water than in o∕w emulsions. While the shape factors could not significantly discriminate between the particles produced in water and o∕w emulsions. The size distribution was in a wide range for water than that for o∕w emulsions. The cavitation erosion mechanism is fatigue failure for water and o∕w emulsions.
Influence of Crystallographic Orientation on Energy Dissipation During Sliding
Authors: Dawkins Jeremy J. , Neu Richard W.
Published: August 2008

The aim of this study is to evaluate a methodology for modeling the influence of crystallographic grain orientation in sliding contacts. The simulations of translating interfering cylindrical asperities, using finite element analysis, were conducted using two different plasticity models for copper: a conventional isotropic, homogeneous J2 plasticity model and a continuum crystal plasticity model. Using crystal plasticity, the dependence of crystallographic orientation on plastic deformation and energy dissipation can be determined. The relative trends predicted using crystal plasticity are consistent with experiments that show friction depends on crystallographic orientation when plastic deformation is one of the primary energy dissipation mechanisms.
EHL Circular Contact Film Thickness Correction Factor for Shear-Thinning Fluids
Authors: Kumar Punit , Khonsari M. M.
Published: August 2008

An extensive set of full elastohydrodynamic lubrication point contact simulations has been used to develop correction factors to account for the effect of shear-thinning lubricant behavior on the central and minimum film thickness in circular contacts under pure rolling condition. The film thickness for a shear-thinning lubricant can be easily obtained by dividing the corresponding Newtonian film thickness by the appropriate correction factor. Comparisons of the film thickness values obtained using the correction factors have been matched with the published experimental results pertaining to shear-thinning lubricants with a variety of realistic flow and piezoviscous properties under a wide range of operating speed. The good agreement between them establishes the validity and versatility of the correction factors developed in this paper.
Running Torque of Ball Bearings With Polymer Lubricant (Running Torque Formulas of Deep Groove Ball Bearings Under Axial Loads)
Authors: Kanatsu Masayuki , Ohta Hiroyuki
Published: August 2008

A running torque analysis was performed on axially loaded deep groove ball bearings lubricated with a polymer lubricant. The analysis included a Type I and a Type II bearing. The Type I bearing has a stamped steel riveted cage with its cavity packed with the polymer lubricant. The ball surface, except for the contact points of the ball and the raceways, was covered with the polymer lubricant. The Type II bearing had the polymer lubricant packed only on the riveted parts of the cage; the balls were not covered with the polymer lubricant. The analysis was applied to a 6206 deep groove ball bearing axially loaded in a range typical of preloads applied in actual application to this size bearing to establish bearing tare torque. The results were compared to an available database. The running torque formulas for deep groove ball bearings with polymer lubricant under axial load were proposed as the sums of the running torque caused by the shearing resistance of the mineral oil between the bearing rings and the polymer lubricant, the elastic hysteresis, the differential slip, the spinning friction of the balls, the elastohydrodynamic lubrication (EHL) viscous rolling resistance, and the friction between the balls and the polymer lubricant (or the cage). The effects of the sources of the running torque were investigated. In the case of the Type I bearing, the running torque caused by the friction between the balls and the polymer lubricant, the EHL viscous rolling resistance, and the shearing resistance of the mineral oil between the bearing rings and the polymer lubricant significantly affect the running torque. In the case of the Type II Bearing, the running torque caused by the EHL viscous rolling resistance and the shearing resistance of the mineral oil between the bearing rings and the polymer lubricant significantly affect the running torque. A reasonable correlation exists between the analysis and the database. However, the analysis needs to be further validated with bearing data from different size deep groove ball bearings run under varying loads and speeds.
Tribochemical Interactions of Friction Modifier and Antiwear Additives With CrN Coating Under Boundary Lubrication Conditions
Authors: Haque T. , Morina A. , Neville A. , Arrowsmith S.
Published: August 2008

In recent years, the optimized use of low friction nonferrous coatings under boundary lubrication conditions has become a challenge to meet the demands of improved fuel economy in automotive applications. This study presents the tribological performance of chromium nitride (CrN) coating using conventional friction modifier (moly dimer) and/or antiwear additive (zinc dialkyl dithiophosphate (ZDDP)) containing lubricants in a pin-on-plate tribometer. Using surface analysis techniques such as the atomic force microscope (AFM) and X-ray photoelectron spectroscopy (XPS), both topographical and chemical analyses of tribofilms were performed. This paper shows that ZDDP and moly dimer both give a positive effect for both low friction and antiwear performance in CrN/cast iron system. Both AFM and XPS analyses give evidence of the formation of ZDDP and moly dimer derived tribofilms on the CrN coating and thus support friction and wear results.
SEED INFECTION OF SOYBEAN BY DIAPORTHE PHASEOLORUM AND ITS INFLUENCE ON HOST DEVELOPMENT
Authors: Wallen V. R. , Seaman W. L.
Published: August 2008

Diaporthe phaseolorum (Cke. & Ell.) Sacc., the causal agent of pod and stem blight of soybeans and generally regarded as a facultative parasite, has been found to be pathogenic during the seedling phase. The fungus caused severe losses of germinating seeds and young seedlings. In 1959 more than 30% of the soybean seed crop in southwestern Ontario was infected, and germination was severely reduced. D. phaseolorum was present in seed samples from this area in 11 of 13 years. Studies with a series of seed samples of varying levels of infection revealed that the fungus was still viable and pathogenic in the seed after storage for 2 years. However, during that time the levels of infection in most samples had decreased markedly whereas a concurrent increase in germinability indicated that infected seeds were killed during the germination phase. While several seed treatment fungicides were effective in increasing germination and emergence in heavily infected samples, none completely controlled the disease. At normal planting rates, yield was not affected by levels of seed infection up to 42% but the yield was significantly lower in a sample containing 73% infected seed. It is concluded that the disease may be important in the seed and seedling phases of host development.
SOME EFFECTS OF TRIS (HYDROXYMETHYL) AMINOMETHANE ON THE GROWTH OF HAEMATOCOCCUS PLUVIALIS FLOTOW
Authors: McLachlan Jack
Published: August 2008

Tris (hydroxyrnethyl) aminomethane was found to inhibit the growth of Haematococcus pluvialis in ASMG medium, which is a modification of ASM medium. This inhibition could be reduced by increasing the calcium concentration of the medium. Other cations, either alone or in combination with calcium, had no effect on Tris toxicity. Tolerance towards Tris was increased in the presence of 5 mM calcium when the initial pH of the medium was increased from pH 7.0 to 8.0 but pH had no effect on Tris tolerance in ASMG medium containing the normal level of calcium. These results with Haematococcus are compared with the results of a previous study on Microcystis aeruginosa.
ENZYME–COENZYME RELATIONSHIPS IN GLUTAMIC ACID METABOLISM OF RUST-INFECTED SUNFLOWER COTYLEDONS
Authors: Smith J. E. , Waygood E. R.
Published: August 2008

The activities of glutamic acid decarboxylase (GDC), glutamic–oxaloacetic transaminase (GOT), and glutamic acid dehydrogenase (GDH) were determined in cell-free extracts of healthy and rust-infected sunflower cotyledons and uredospores. Uredospore extracts contained an active DPN-linked GDH, but little or no GDC or GOT activity. The activity of GDC was lower and that of GOT higher in extracts of rust-infected tissue as compared to healthy tissue due to a redistribution of their coenzyme, pyridoxal phosphate. The activity of GDH was higher in 'rusted' extracts due to the presence of the similar fungal enzyme. It is suggested that this contribution of GDH by the fungus to the host–parasite complex alters the normal coenzyme pattern of other enzymes metabolizing glutamic acid.
THE TAXONOMY OF SOME NORTH AMERICAN SPECIES OF CHRYSOSPLENIUM L., SECTION ALTERNIFOLIA FRANCHET
Authors: Packer J. G.
Published: August 2008

A reappraisal is presented of the taxonomy of three of the four alternate-leaved species of Chrysosplenium occurring in North America, namely C. tetrandrum, C. iowense, and C. Rosendahlii, the latter a new species described for the first time. The investigation demonstrates that the species can be readily separated morphologically even as seedlings. Each morphological entity is characterized by a different chromosome number, C. tetrandrum 2n = 24, C. Rosendahlii 2n = 96. C. iowense 2n = c.120, and a distinctive geographical distribution. C. iowense, which has on occasions been regarded as identical with C. alternifolium var. sibiricum, is retained as a species in the absence of a modern taxonomic analysis of the Old World species C. alternifolium.
CHARACTERISTICS OF DOUGLAS-FIR ROOT SYSTEMS
Authors: McMinn R. G.
Published: August 2008

The root systems of 28 Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) in four stands, aged 10, 25, 40, and 55 years, were excavated hydraulically to determine the rooting characteristics of trees in different crown classes at various ages. The extent, depth, configuration, rooting density, and mycorrhizal component of root systems were examined. The significance of the characteristics observed is discussed in relation to silviculture, nursery practice, and forest pathology.
A NOTE ON THE GREATLY REDUCED ABILITY OF FUCUS VESICULOSUS TO ABSORB OR EVOLVE CO2 WHEN NOT SUBMERGED
Authors: Bidwell R. G. S. , Craigie J. S.
Published: August 2008

The rockweed, F. vesiculosus, inhabits the littoral zone and is exposed for a large part of the time between tides. It is shown that this weed fixes or evolves CO2 at a greatly reduced rate when exposed, even if its surface is wet and the atmosphere surrounding it is saturated with water.
A COMMUNITY OF ARCTIC–ALPINE PLANTS ON THE EAST SHORE OF LAKE SUPERIOR
Authors: Soper James H. , Maycock Paul F.
Published: August 2008

This paper reports the discovery of a community of arctic–alpine plants on the cliffs, rocky ledges, and boulder beaches along the south shore of Old Woman Bay. The site is located on the east shore of Lake Superior at approximately 47° 47′ N. lat., 84° 54′ W. long., in the District of Algoma, Ontario. Reference is made to earlier reports of arctic–alpine plants occurring in the Lake Superior region and to important collections from the north and east shores of the lake already available in herbaria. A description is given of the site at Old Woman Bay and of the plant community discovered there, together with a presence list of 40 species of vascular plants. Collections made at the site are cited in an annotated list and distribution maps with special comments are provided for the following species: Woodsia alpina, Trisetum spicatum var. pilosiglume, Polygonum viviparum, Sagina nodosa, and Saxifraga aizoön var. neogaea. A list of bryophytes is also included.It is suggested that the arctic–alpine species reached the Old Woman Bay region by a natural migration during or soon after the retreat of the last glaciers of the Wisconsin stage of the Pleistocene ice age. Later the boreal forest invaded the area but the arctic–alpine species have been able to survive on the rocky shores where suitable habitats with cooler microclimatic conditions prevail. This explanation entails assuming an age for the community in the order of at least several thousand years. The possibility of recent introductions of these species is considered improbable.
PHOTOSYNTHESIS AND METABOLISM IN MARINE ALGAE: VI. THE UPTAKE AND INCORPORATION OF S35-SULPHATE IN FUCUS VESICULOSUS
Authors: Bidwell R. G. S. , Ghosh N. R.
Published: August 2008

The uptake and fixation of S35-labelled sulphate in the rockweed Fucus vesiculosus has been examined using direct chromatography of ground tissue as well as conventional techniques. The uptake of sulphate, unlike that of carbonate, is complex and not directly related to internal requirement. Both the uptake and fixation of sulphate are increased by light. Sulphate appears to penetrate into the thallus with difficulty: cut tissue took up sulphate much faster than undamaged tissue, the rate of uptake being roughly proportional to the area of cut surface, not to the area of intact surface. Frozen and ground tissue retained its ability to convert sulphate into organic forms for a short time. An active exchange of the sulphate portion of the sulphated polysaccharide, fucoidin, was detected. The incorporation of S35into fucoidin was 20 to 600 times greater than that of C14, depending on the duration of the experiments.
THE SUPPRESSION OF GROWTH RINGS IN JACK PINE IN RELATION TO DEFOLIATION BY THE SWAINE JACK-PINE SAWFLY
Authors: O'Neil L. C.
Published: August 2008

An investigation of the radial growth of jack pine (Pinus banksiana Lamb.) defoliated by the Swaine jack-pine sawfly (Neodiprion swainei Midd.) disclosed that growth rings were discontinuous and missing in cross-sectional disks from severely damaged trees. In young and open-grown trees with dead tops, the incidence of such deficiencies in radial growth was especially high in disks from upper regions of the stems, in the vicinity of the dead tops; radial growth was suspended for 1 year and subsequently resumed in disks from the lower regions of some stems. Cambial inactivity was more generalized in trees from an old and dense stand and it was detected in disks representing major portions of some of the stems sampled; the death of some trees followed 2 to 6 years of cambial inactivity in disks cut at various heights along their entire stems. Growth deficiencies in the young stand were clearly effects of severe sawfly defoliation. Data from the old, dense stand indicated that sawfly defoliation had perhaps merely hastened the gradual deterioration of the stand in which intertree competition was intense.
CYTOSPORA CANKER OF POPLARS: BARK WOUNDING IN RELATION TO CANKER DEVELOPMENT
Authors: Bloomberg W. J. , Farris S. H.
Published: August 2008

Cuttings of Populus trichocarpa Torr. and Gray, P. × canadensis Moench 'Regenerata' and P. × canadensis ‘Robusta Bachelieri’ were adjusted to three different moisture contents, then wounded by scorching the bark. The moisture treatments differed significantly in their effects on the histological responses in tissues around the scorch wounds, the greatest contrast being in the mode of tannin deposition. Lignification was also affected by moisture content; however, fewer cells were involved in lignin changes than in tannin deposition. No suberization was observed as a result of wounding. There were qualitative and quantitative differences among the poplar varieties with respect to tannin deposition.When wounds were inoculated with Cytospora chrysosperma (Pers.) Fr., the growth of canker varied inversely as the number of tanniferous cells, the width of the tanniferous zone, and the number of lignified cells. The correlation with tannin deposition was much stronger than that with lignification. These findings suggested that the relationship previously observed between Cytospora canker growth and moisture content may operate partly through the mechanism of tannin deposition.
TRIMETHYLAMMONIUM COMPOUNDS IN TILLETIA SPP.
Authors: Nielsen J.
Published: August 2008

Spores of Tilletia contraversa Kühn, T. laevis Kühn, and T. caries (DC.) Tul. were found to contain ergothioneine, choline, betaine, and probably hercynine, as well as two unidentified trimethylammonium compounds. These substances, with the exception of betaine, were also detected in haploid mycelium of T. contraversa and in its culture filtrate. One or more of these compounds could act as precursors for the trimethylamine released by bunt spores.
THREE NEW SPECIES OF BOTRYOTINIA ON RANUNCULACEAE
Authors: Hennebert G. L. , Groves J. W.
Published: August 2008

Three new species of Botryotinia on Caltha palustris L., Ranunculus septentrionalis Poir., and Ficaria verna Huds. (Ranunculaceae) are described as B. calthae Hennebert and Elliott, B. ranunculi Hennebert and Groves, and B. ficariarum Hennebert. Each of the three species has a Botrytis state of the B. cinerea complex, and they thus constitute additions to the species already segregated from that complex, i.e. Botryotinia fuckeliana, B. convoluta, B. draytoni, and B. pelargonii. The Botrytis state of B. ficariarum can be distinguished morphologically.While B. ranunculi is a North American species and B. ficariarum an European one, B. calthae is reported from both continents.
CHARACTERISTICS OF A HYBRID BIRCH AND ITS PARENT SPECIES
Authors: Clausen Knud E.
Published: August 2008

The ranges of variation in 24 morphological characteristics, 3 anatomical characteristics, and 1 chemical characteristic were studied in a Minnesota population consisting of 150 bog birches (Betula pumila var. glandulifera), 150 paper birches (B. papyrifera), and 47 individuals of their natural hybrid (B. × sandbergii). The hybrid resembled paper birch in having few stems and a long leaf petiole, but was intermediate between its parents in stem height and diameter, dimensions and positions of male and female catkins, size of fruit wings, and 10 leaf characteristics. Hybrid pollen was as large as that of paper birch. In bark color and exfoliation the hybrid group covered the range of both parents, but most hybrids resembled bog birch in bark characteristics. Shape of fruit bracts was different for each taxon. The hybrid was intermediate in leaf midvein anatomy, but resembled bog birch in number of stomates and paper birch in stomatal size. Paper chromatography revealed the presence of unidentified fluorescent compounds in the inner bark. Chromatographic results permitted identification of the parental species but lacked consistency in the hybrids.
INFECTION TESTS WITH TWO CAULICOLOUS RUSTS OF JACK PINE IN SASKATCHEWAN
Authors: Zalasky H. , Riley C. G.
Published: August 2008

The identity of Peridermium stalactiforme Arth. & Kern and its occurrence on Pinus banksiana Lamb, in Saskatchewan are established. Melampyrum lineare Desr. and Castilleja rhexifolia Rydb. were infected with this rust experimentally. For the first time, C. rhexifolia was discovered to be naturally infected with a species of Cronartium. The minimum period from inoculation to production of mature spores was 14 days for uredinia and 16 for telia. In 18 experiments, 17 inoculations on C. rhexifolia produced sparse infection in 30 of the 37 clusters inoculated, and 6 inoculations of Melampyrum lineare plants produced more severe infection in 48 out of 97 plants. In contrast, 59 experiments with Peridermium harknessii J. P. Moore involving 109 inoculations of 1344 M. lineare plants and 48 clusters of Castilleja rhexifolia failed to produce infection, indicating that these suspects are not hosts of P. harknessii.
A MUTATION IN PUCCINIA RECONDITA ROB. EX. DESM. F. SP. TRITICI TO VIRULENCE ON TRANSFER, CHINESE SPRING × AEGILOPS UMBELLULATA ZHUK.
Authors: Samborski D. J.
Published: August 2008

A culture of wheat leaf rust, Puccinia recondita Rob. ex. Desm. f. sp. tritici, producing infection type 1 + on Transfer wheat was shown to be heterozygous for virulence at the locus conditioning this infection type, with virulence being incompletely dominant. Aegilops umbellulata Zhuk., the source of the resistance carried by Transfer, was highly resistant to cultures that were homozygous avirulent with respect to the Transfer gene and to cultures heterozygous for virulence to this gene, but it was only moderately resistant to cultures homozygous for virulence to the Transfer gene. Although other species of Aegilops tested varied in reaction from resistant to susceptible, each reacted in the same way to cultures which were either virulent or avirulent on Transfer.
THE DISTRIBUTION AND FREQUENCY OF OCCURRENCE OF PHYSIOLOGIC RACES OF PUCCINIA CORONATA CORDA F. SP. AVENAE ERIKSS., IN CANADA, 1952 TO 1961
Authors: Fleischmann G. , Samborski D. J. , Peturson B.
Published: August 2008

From 1952 to 1956 the races of crown rust, Puccinia coronata Corda f. sp. avenae Erikss., that predominated in Eastern Canada were 201, 202, 203, 209, 239, and 240. Races 201, 202, and 204 occurred most frequently in Western Canada. These races cannot attack the differential host variety Victoria, from which the currently grown commercial varieties Rodney and Garry derive their resistance. Garry and Rodney became widely grown in Canada by 1957, and since then races 216 and 274, which can attack Victoria, have become prominent, especially in Western Canada.More races are found in Eastern Canada than in the west, and there is less tendency for a few races to predominate in the east. These differences may be explained by the relatively frequent occurrence of the alternate host, Rhamnus cathartica L., in important oat-growing regions of Eastern Canada, and by the cultivation of large acreages of a few varieties with similar resistance in the west. The most important factor affecting the distribution and frequency of occurrence of races is the variety grown.
A NEW SPECIES OF DIMARGARIS FROM INDIA
Authors: Mehrotra B. S. , Baijal Usha
Published: August 2008

A new species of the genus Dimargaris was isolated from cow dung manure at Allahabad. It is characterized by the presence of oblong spores and has been named D. oblongispora Mehrotra and Baijal n. sp.
STUDIES IN THE GENUS CALICIOPSIS
Authors: Funk A.
Published: August 2008

Three species of the genus Caliciopsis, all of which produce cankers on conifers, were investigated with respect to development, morphology, general biology, and pathogenicity. Caliciopsis orientalis is described as a new species. Developmental studies have shown that the ascocarps originate from the surface of an erumpent stroma. The female sexual structures are formed from dark-staining hyphae which arise in the core of the young ascocarp. Certain of these hyphae send out trichogynes which penetrate to the outside of the ascocarp. The hyphae enlarge greatly and produce clusters of ascogonia by a budding process or through meristogenous division of the hyphal cells. The ascogonia may further divide by septum formation and thus become multicellular. Septate, branching ascogenous hyphae grow out from the ascogonia and give rise to tufts of asci from the terminal cells. The stalks of the asci elongate enormously as they are carried up into the hymenium. Homologous development and structure were shown in several members of the Caliceaceae. Differences in the final appearance of the hymenium were attributed to the absence of extensive ascogenous hyphae in the Caliceaceae, but the fundamental similarities were interpreted as evidence of a phylogenetic relationship with Caliciopsis. Comparison of the asci, hymenium, and general habit of two genera of the Coryneliaceae with Caliciopsis confirmed the opinion of previous workers that the two groups are related. Observations on fruiting cycles revealed developmental correlations which indicated the possibility of functional spermatia, but experimental spermatization failed to prove this. Data on spore dissemination, germination, and penetration were also gathered. Canker anatomy and host–parasite relationships were elucidated. Pure cultures were obtained from both spermatia and ascospores. The latter were used to determine nutritional requirements of the fungus by measuring growth response to 14 carbon compounds, 5 nitrogen sources, and 7 vitamins. The effects of pH, temperature, and aeration on vegetative growth in pure culture were also studied. Extensive field observations revealed that one species (C. pseudotsugae) is widespread in British Columbia on three native conifers, and that in addition to primary pathogenicity it offers opportunities for associative effects to other forest pathogens which may result in serious damage. Behavior in pure culture confirmed the evidence of association between the pathogens involved. Pathogenicity was proved by extensive field inoculations.
MORPHOGENETIC STUDIES ON EXCISED LEAVES OF OSMUNDA CINNAMOMEA L.: MORPHOLOGICAL STUDIES OF LEAF DEVELOPMENT IN STERILE NUTRIENT CULTURE
Authors: Caponetti James D. , Steeves Taylor A.
Published: August 2008

The growth and development of certain frond primordia from the apical bud of the fern Osmunda cinnamomea, after explantation to sterile nutrient medium, are described. External morphological changes in developing cultured fronds have been followed carefully from the time of excision to the attainment of maturity and have been compared with corresponding developmental changes in natural fronds. It has been concluded that the morphogenetic pattern in excised fronds is qualitatively normal in spite of isolation from the parent plant, strongly suggesting that the control of this pattern is autonomous within the organ. There are, however, significant quantitative discrepancies between cultured and natural fronds which require histological analysis.
THE LEPTOGRAPHIUM COMPLEX: PENICILLIUM REPENS C. & E.
Authors: Kendrick W. Bryce
Published: August 2008

Penicillium repens C. & E. is transferred to the genus Phialocephala Kendrick, and is redescribed and illustrated from the type, another authenticated collection, and a recent collection and isolation.
ENDRIA INIMICA (SAY), A NEW LEAFHOPPER VECTOR OF A CELERY-INFECTING STRAIN OF ASTER-YELLOWS VIRUS IN BARLEY AND WHEAT
Authors: Chiykowski L. N.
Published: August 2008

A celery-infecting strain of aster-yellows virus was transmitted by Endria inimica (Say) from Vantage barley to Vantage barley and Ramsey durum wheat. With 8-hour acquisition feeds, an average of 12.4% of the insects became infective. Maximum infectivity, approximately 30%, was reached with 24-hour feeds and no further increase was recorded with longer periods of up to 7 days. The minimum latent period of the virus in the insect was between 18 and 25 days while the maximum period recorded was between 73 and 81 days.
THE EFFECT OF A TEMPERATURE SHIFT ON MATING IN CHLAMYDOMONAS EUGAMETOS
Authors: Trainor Francis R. , Roskosky Frances G.
Published: August 2008

The effect of various temperature combinations on the mating reaction in Chlamydomonas eugametos was determined. Over 90% pairing was observed when mating types were suspended in ammonium nitrate deficient medium in the light at 30 °C for 12 hours and then immediately stored in darkness at 22 °C. Up to 60% pairing has been obtained using other temperature combinations, but the best results were always with the broader temperature shift. Darkness was not essential, but arrested the reaction at pairing and introduced uniformity to the results. The 30 °C−22 °C light–dark shift was shown to be optimal both when mating types were mixed during ammonium nitrate starvation and when held separate during starvation.
MICROFUNGI: IX. MENISPORA PERSOON
Authors: Hughes S. J. , Kendrick W. B.
Published: August 2008

Six species assigned to Menispora in North America and Europe are redescribed and illustrated. The history of Menispora and its synonyms is traced.
PROTEIN TURNOVER IN WHEAT AND SNAPDRAGON LEAVES: PRELIMINARY INVESTIGATIONS
Authors: Hellebust J. A. , Bidwell R. G. S.
Published: August 2008

Detached primary wheat leaves and attached cotyledons and primary leaves of snapdragons were allowed to photoassimilate C14O2for short periods of time. They were subsequently kept in air and samples were taken at various time intervals and analyzed for protein nitrogen, and amounts and total radioactivities of soluble sugars and amino acids and protein amino acids. A method of estimating protein turnover from these data is discussed. Amounts and specific activities of respired carbon were also determined for wheat leaves.Minimum protein turnover rates of about 0.5 to 1.5% per hour were found in rapidly growing snapdragon leaves and in snapdragon cotyledons. Lower rates were found in detached, non-growing wheat leaves and slowly growing snapdragon leaves. Little contribution could have been made by proteins as substrates for respiration in detached wheat leaves. It is suggested that protein turnover in leaves is mainly associated with growth and biochemical differentiation.
TAXONOMICAL VALUE OF ALISMA TRIVIALE PURSH AND ALISMA SUBCORDATUM RAFIN
Authors: Pogan Eugenia
Published: August 2008

Detailed morphological and karyological studies have revealed that the North American taxa of the Alisma plantago-aquatica complex are most appropriately classified as the two species, A. subcordatum Rafin. (2n = 14), and A. triviale Pursh (2n = 28). The morphological characters separating these species and distinguishing them from the European diploid, A. plantago-aquatica L., s. str., are given, and also the chromosome number of American material of A. gram-ineum Gmel. (2n = 14).
THE LEPTOGRAPHIUM COMPLEX: TWO NEW SPECIES OF PHIALOCEPHALA
Authors: Kendrick W. Bryce
Published: August 2008

Two new species are described in the lignicolous Hyphomycete genus Phialocephala Kendrick, and a key is given to the members of the genus.
THE GENUS BASIDIODENDRON
Authors: Luck-Allen E. Robena
Published: August 2008

Sebacina, Exidiopsis, and Basidiodendron, three genera of the resupinate tremellaceae, are recognized. Sebacina, based on Thelephora incrustans Pers. ex Fries, is retained (in sensu stricto). Exidiopsis, established for Exidia effusa Bref., is accepted as a genus. The taxon Bourdotia, originally created by Bresadola in 1908 as a subgenus with Sebacina (Bourdotia) galzinii as the type and in 1913 elevated by Bresadola and Torrend to generic rank, is proposed as a subgenus of Exidiopsis. Since Bourdotia galzinii is the type of Bourdotia, the generic name Basidiodendron created by Rick in 1938 in order to accomodate B. luteo-griseum is reinstated for the arid-reticulate gloeocystidiate species formerly included in Bourdotia. Two subgenera of Basidiodendrcn are recognized, namely the type subgenus Basidiodendron established for B. luteo-griseum Rick and Asarcogloea subg. nov. based on Sebacina pini Jacks. & Martin. The type subgenus Basidiodendron includes six species. In Asarcogloea, there are four species involved. Two of these, B. subreniformis sp. nov. and B. nodosa sp. nov., found in Ontario inhabiting decaying wood, are described for the first time. Taxonomic keys and illustrations are included for these species.
NOTEWORTHY PLANT SPECIES AND COMMUNITIES IN WESTCENTRAL ALBERTA
Authors: Moss E. H. , Pegg George
Published: August 2008

This paper reports significant extensions of range for 71 vascular species and discusses the occurrence of several of these plants in relation to postglacial development of the flora of westcentral Alberta. Some attention is paid to the coniferous vegetation of the region, especially those faciations in which certain of the more interesting species occur. The alpine fir and black spruce faciations are regarded as edaphic climax types in the upland forest. Species new to Alberta include the "eastern" Rhynchospora capillacea, the rare Sparganium glomeratum, and the "Pacific" Streptopus streptopoides var. brevipes. Two other "Pacific" species, Angelica genuflexa and Tiarella trifoliata, previously known in the area from isolated collections, are now reported as widespread and locally abundant. Floristic data support the hypothesis of a fluctuating ice-free corridor as a refugium in western Alberta during the late Wisconsin or soon thereafter, and point to Manitoba–Saskatchewan–Alberta as a vast meeting ground of "eastern" and "western" biota.
THE GENUS SCIRPUS LINN.: CRITICAL SPECIES OF THE SECTION PTEROLEPIS
Authors: Koyama Tetsuo
Published: August 2008

The section Pterolepis is expanded to include section Schoenoplectus. Critical species of this section are discussed in detail with particular emphasis on North and South American relationships. A key to all known species is provided. The following new combinations are proposed: S. americanus ssp. monophyllus, S. americanus ssp. monophyllus var. conglomeratus, S. × contortus, S. littoralis var. capensis, and S. californicus ssp. Tatora.
THE GENUS ZALERION MOORE & MEYERS
Authors: Anastasiou C. J.
Published: August 2008

The genus Zalerion is reconstituted to include Z. maritima (Linder) comb. nov. and a new species from salt lakes, Z. varia. Z. nepura Moore & Meyers, Z. eistla Moore & Meyers, Z. xylestrix Moore & Meyers, Z. raptor Moore & Meyers, and Helicoma salinum Linder are placed into synonomy with Z. maritima.
FIVE GENES LOCATED ON CHROMOSOME 4 OF THE TOMATO
Authors: Butler L.
Published: August 2008

The gene for broadleaf has been the only gene known to be on chromosome 4 of the tomato. Four other genes are shown to be linked with broadleaf. These are wiry (w1), which distorts the leaves and flowers; clausa (clau), which causes excessive proliferation of the pinnae; divergens (di) which affects plant growth and stem color; and stamenless (sl1), which causes the stamens to be absent or greatly reduced. The genes w1, clau, and di give mongenic ratios which are deficient in number of mutants. The order of the genes on the basis of F2 data is w1clau 39 e 21 di 2 sl1. The genes tf, ao, rv, and ah are not in this group.
UN HYPHOMYCÈTE NOUVEAU ARACHNOPHORA FAGICOLA GEN. NOV. SPEC. NOV.
Authors: Hennebert Grégoire L.
Published: August 2008

A new hyphomycete, Arachnophora fagicola, is described from the cupules of Fagus sylvatica in Belgium, constituting the single species of a new annellosporous form-genus.
GROWTH RATES OF CLADONIA ALPESTRIS, C. MITIS, AND C. RANGIFERINA IN THE TALTSON RIVER REGION, N.W.T.
Authors: Scotter George W.
Published: August 2008

Data on the growth rate of lichens are essential to the understanding of the carrying capacities of rangelands used by caribou and reindeer in Canada. Recent Russian literature suggests fruticose lichens have three growth stages. The first stage is one of podetium accumulation. During the second stage, accumulation rate and decomposition rate are similar, while, in the third stage, decomposition of the Podetium is more rapid than accumulation. In the Taltson River region, the average annual linear growth rates of Cladonia alpestris, Cladonia mitis, and Cladonia rangiferina as determined by dividing the number of joints on the living podetium by the height of the living portion of the podetium, are 3.4, 3.6, and 4.1 mm, respectively. These rates are less than those reported from Russia, Newfoundland, and northern Saskatchewan.
ASCOSPORE DISCHARGE AND CONIDIUM RELEASE BY NECTRIA GALLIGENA BRES. UNDER FIELD AND LABORATORY CONDITIONS
Authors: Lortie Marcel , Kuntz James E.
Published: August 2008

Ascospore discharge and conidium release of Nectria galligena Bres. from cankers on yellow birch (Betula alleghaniensis Britt.) were investigated under field conditions and were related to prevailing rainfall, relative humidity, and temperature. Release of conidia was associated with splashing rain whereas ascospores were discharged during or after rain. Conidia were trapped only from May through August during the period of active growth of the host, and showed a peak in May and June. In contrast, ascospores were trapped on rainy days throughout the year, including mid-winter when temperatures were around the freezing point. Maximum ascospore discharge occurred in August and September. In the laboratory, ascospores were discharged as wetted perithecia began to dry out. Both relative humidity and temperature affected the rate of perithecial drying and thus the rate of release and duration of discharge of ascospores. The results are discussed with respect to environmental conditions that prevail in eastern Canada during winter.
GENERIC CORRELATIONS AND CONCEPTS: BROOMELLA AND PESTALOTIA
Authors: Shoemaker R. A. , Müller Emil
Published: August 2008

The type and three additional species of Broomella from Clematis were treated as congeneric because of similar ascocarp structure, and because of the nature of the unitunicate asci, which, in all species, have a pulvillus (a subapical chitinoid body, "le coussinet chitinoïde"), but lack an iodine-reactive ring. Moreover, all the species have distinctive ascospores that are triseptate, pigmented only in the central cells, and furnished with one simple seta at each end. The conidia, like the ascospores, are four-celled with pigment only in the two central cells, but variously setose at the ends, and are produced on annellophores. Although two species have conidia with a single apical seta typical of Monochaetia, and two have multiple or branched setae typical of Pestalotia, the former generic dispositions of the conidial states made on numbers of setae and on fruit-body form were rejected and the conidial states united under one generic name, Pestalotia.Broomella vitalbae (Berk. & Broome) Sacc., the generic type, collected on Clematis vitalba L. in southern France, produced conidia with one simple seta at each end, and non-germinable microconidia (spermatia) when cultured. The conidial state is named Pestalotia vitalbae n. sp. North American collections of Broomella montaniensis (Ell. & Ev.) E. Müller & Ahmad on Clematis ligusticifolia Nutt. consistently bore the associated conidial state first described as Arthrobotryum pestalozzioides Dearness & Fairman in Fairman with which Pestalotia berberidis Guba was found to be conspecific. Pestalotia pestalozzioides (Dearness & Fairman in Fairman) n. comb. is proposed for the conidial state. Broomella excelsa collected in Pakistan on Clematis sp. and described as new was found in close association with the conidial state Ahmadinula excelsa Petrak for which Pestalotia excelsa (Petrak) n. comb. is proposed. Broomella acuta on Clematis flammula L. from southern France is described as new. Cultures from its ascospores and from conidia of Pestalotia truncata Lév. found on the same gathering, produced identical conidia, and, in addition, formed microconidia similar to those of Broomella vitalbae.
MIDDAY CLOSURE OF STOMATA IN AGING TOBACCO LEAVES
Authors: Macdowall F. D. H.
Published: August 2008

The average stomatal widths in the lower epidermis of tobacco leaves at a given stem position in a crop were estimated repeatedly through a number of days during the growing season using a calibrated infiltration method. Stomata started opening more than an hour before morning twilight. Stomata in newly matured leaves stayed wide open until dark but with increasing leaf age the stomata closed earlier, as early as late morning, and this midday closure was then followed by reopening in the afternoon. The known closing effect of high light intensity was confirmed. There was also a significant daily correlation between stomatal width and soil moisture content both of which decreased through the season. Leaf moisture stress was assumed to be accentuated with leaf age. Comparisons of light saturation curves for the afternoon closure in old leaves indicated the presence of a more limited light reaction than that evident in morning opening or in the photoactive closure in younger leaves. Reasons are given for proposing that a well-known light reaction supports an active stomatal opening mechanism.
EVIDENCE FROM INCREASE IN RIBONUCLEIC ACID AND PROTEIN SYNTHESIS IN AUTUMN FOR INCREASE IN PROTOPLASM DURING THE FROST-HARDENING OF BLACK LOCUST BARK CELLS
Authors: Siminovitch D.
Published: August 2008

The changes occurring in the ribonucleic acid and desoxyribonucleic acid of the living bark cells of the black locust tree in autumn have been followed in relation to the increases which take place at the same time in the water-soluble proteins, rate of incorporation of glycine into protein, and frost resistance.An increase in the ribonucleic acid without a change in the desoxyribonucleic acid has been shown to occur and to precede the period of maximal increase in rate of incorporation of glycine into protein, net synthesis of protein, and increase in freezing resistance.Because the increase in proteins is closely associated with the development of resistance to freezing injury in the bark, it is suggested that this transformation of the protein synthetic capacities of the bark, and the augmentation of protoplasmic substance which results from it, is part of the seasonal processes of adaptation of the tree to freezing. It is suggested that, in this process of adaptation, the function of the augmentation of the protoplasm is to so change the physical properties of the cell protoplasm as to enable it to withstand the effects of freezing.
THE BLUEBERRY RHIZOME: IN VITRO CULTURE
Authors: Barker W. G. , Collins W. B.
Published: August 2008

The successful in vitro culturing of blueberry (Vaccinium angustifolium Ait). rhizome apices is reported. A variation in sensitivity to short light exposures is noted that may be seasonal. In spring the organ appears less light sensitive. Later no exposure is tolerated without response. In dark culture of spring-gathered rhizomes, the diageotropic habit continues with the evolution of scale leaves separated by long internodes. Exposure to a 16-hour light/dark cycle, however, causes the apex to elevate and induces changes in habit that are manifested by the shortening of the internode and the expansion of the scales into green leaves. Elongating growth essentially ceases. Histological studies suggest that a disruption of the apex follows light exposure. Necrotic cells appear behind the dome, and the meristem decreases in size and changes shape even as it rapidly evolves foliar initials. Apparently the meristem rapidly loses function.The method is offered as a technique suitable for the controlled study of rhizome physiology and development.
A NEW GENUS OF PHACIDIACEAE ON PICEA MARIANA
Authors: Darker Grant D.
Published: August 2008

A new phacidiaceous genus, Micraspis, is erected to accommodate a single species, M. acicola, on Picea mariana (Mill.) B.S.P. from Northern Ontario. Its probable conidial state is described as Periperidium acicola gen. et sp. nov.
GENETIC DIFFERENCES IN LEAF ABSCISSION AND THE ACTIVITY OF NATURALLY OCCURRING GROWTH REGULATORS IN PEACH
Authors: Weaver G. M. , Jackson H. O.
Published: August 2008

Leaf abscission in peach is correlated with the release of tryptophan into the cytoplasm following a sudden drop in air temperature below the physiological minimum. The tryptophan accumulates in the variety Elberta and results in increased activity levels of 5-hydroxytryptamine, 5-hydroxyindoleacetic acid, and an unidentified neutral growth promoter. The rapid defoliation of the canker resistant variety Elberta was, however, associated more closely with the endogenous levels of tryptophan and 5-hydroxytryptamine. Susceptible Dixired variety, which defoliates slowly, contains lower activity levels of these compounds at the time of leaf abscission, and shows enhanced activity of kynurenic and xanthurenic acids throughout this same period. This suggests that tryptophan does not accumulate in Dixired to cause rapid abscission because of a greater genetic capacity for degradation by way of the kynurenine, hydroxyanthranilic, nicotinic acid pathway common in the metabolism of animals.
GENERIC CORRELATIONS AND CONCEPTS: GRIPHOSPHAERIOMA AND LABRIDELLA
Authors: Shoemaker R. A.
Published: August 2008

The connection of the type species of Griphosphaerioma von Höhnel with its conidial state, the type species of Labridella Brenckle was accepted. Griphosphaerioma kansensis (Ell. & Ev.) n. comb. (= G. symphoricarpi Rehm ex von Höhnel) lias unitunicate asci, with a pulvillus, but, unlike the type species of Griphosphaeria and Clathridium, without an amyloid ring. The conidial state of Griphosphaerioma unlike the conidial states of Griphosphaeria and Clathridium produces only one conidium on each conidiophore. The Labridella conidial state is segregated from Pestalotia de Notaris as Labridella comu-cervae Brenckle because of its unique conidia and the manner of their formation.The pyrenomycete first described as Plowrightia symphoricarpi Ell. & Ev. associated on Symphoricarpos with Griphosphaerioma and sometimes confused with it, but distinguished by bitunicate asci, phaeodidymous ascospores, and a pseudoparenchymatous ascocarp wall is renamed Gibbera andersonii. A revised synonymy, illustrations, and a description are provided for both species.
THE LIFE-FORMS OF THE FLORA OF MOUNT YAMASKA, ROUVILLE COUNTY, QUEBEC
Authors: LeBlanc S. C. Fabius
Published: August 2008

The life-forms of the flowering plants and vascular cryptogams of the flora of Mount Yamaska, Quebec, are listed according to the system developed by C. Raunkiaer. Four life-form spectra have been established. Spectra including vascular cryptogams do not vary significantly from those without vascular cryptogams; spectra including both naturalized and native species vary somewhat from those including native species only. The life-form spectrum of native and naturalized phanerogams is compared with similar spectra from other localities in eastern North America.