Pluteus insidiosus Complex, Four New Species Described and Pluteus reisneri Resurrected.

We studied the taxonomy of Pluteus insidiosus and similar species using morphological and molecular (nrITS, TEF1-α) data, including a detailed study of the type collection of P. insidiosus. Based on our results, we recognize five species in this group: P. insidiosus sensu stricto and four other taxa: P. assimilatus; P. farensis; P. flavostipitatus; and P. pseudoinsidiosus; described here as new. All these taxa are distinct from each other based on molecular data, but some of them are semi-cryptic based on morphology and co-occur in the Palaearctic region. An additional molecular lineage, phylogenetically separates from the P. insidiosus complex, but with many morphological similarities, was recognized in the molecular phylogenies. Based on the revision of available type collections, the name Pluteus reisneri Velen., was adopted for this Clade. Pluteus reisneri was validly published in 1921, but it has barely been used since its original description. A modern epitype, with molecular data, was selected for P. reisneri.

Jakob Emanuel Lange: The man and his mushrooms.

Jakob Emanuel Lange (1864-1941), Danish mushroom taxonomist and illustrator, was an agricultural educator and economic philosopher. A follower and translator of the American Henry George, Lange was Headmaster of a "Small-holders High-School," which served as a model for American folk-schools. Lange visited North America on three occasions. The first, in 1927, relied on his professional expertise; the second, in 1931, was purely mycological; and the third, 1939, was a combination of the two. All of this was lived against two World Wars and the Great Depression. This paper summarises the circumstances of Lange's life against a background of the American mycologists of the day, the ominous events over his adult lifetime and his magnum opus, "Flora Agaricina Danica", of five volumes illustrating ca. 1200 species on 200 coloured plates.

A survey of Hebeloma (Hymenogastraceae) in Greenland.

This is the first study exclusively dedicated to the study of Hebeloma in Greenland. It is based on almost 400 collections, the great majority of which were collected by three of the co-authors over a period of 40 years and were lodged in the fungarium of the Natural History Museum in Copenhagen. The material was identified using molecular and morphological methods. In total, 28 species were recognized, 27 belonging to three sections, H. sects Hebeloma, Denudata and Velutipes. One species sampled was new to science and is here described as H. arcticum. For all species, a description, a distribution map within Greenland and macro and microphotographs are presented. A key is provided for the 28 species. The distribution of species within Greenland is discussed. The findings are placed in the context of studies of arctic and alpine Hebeloma from other parts of the world where comparable data exist. Notably, H. grandisporum, H. louiseae and H. islandicum, previously only known from Romania, Svalbard, Iceland or Norway, respectively, have been found in Greenland. The latter is also the only species encountered that does not belong to any of the above sections. Hebeloma excedens and H. colvinii - for the latter we here publish the first modern description - are to date only known from continental North America and now Greenland.

Volvariella turcica, a new species from Turkey, and a multigene phylogeny of Volvariella.

A new species of Volvariella, collected from Aydin Province on the coast of the Aegean Sea in southwestern Turkey, is described as Volvariella turcica, sp. nov., based on morphology and multigene molecular analysis of three nuc rDNA gene regions: internal transcribed spacer ITS1-5.8S-ITS2 (ITS), 28S, and 18S. The new species was found in forests dominated by Pinus brutia and Quercus coccifera and mainly characterized by small basidiomata with a white pileus covered with pale ochre center and an ochre-discoloring volva, small basidiospores, lageniform pleurocystidia, balloon-shaped to clavate cheilocystidia, and stipitipellis hairs that are cylindrical or cylindrical-tortuous with subcapitate or lobe-like projections. A comprehensive description, illustrations, and line drawings are provided, and comparison with morphologically similar and phylogenetically related species is discussed.

The smut fungi of Greenland.

The first taxonomic treatment of the smut fungi in Greenland is provided. A total of 43 species in 11 genera are treated and illustrated by photographs of sori, microphotographs of spores in LM and SEM, and distribution maps. Two species, Anthracoidea pseudofoetidae and Urocystis tothii, are recorded as new from North America. Thirteen species, Anthracoidea altera, A. capillaris, A. limosa, A. liroi, A. pseudofoetidae, A. scirpoideae, A. turfosa, Microbotryum lagerheimii, M. stellariae, Schizonella elynae, Stegocintractia luzulae, Urocystis fischeri, and U. tothii, are reported for the first time from Greenland. Three new fungus-host combinations, Anthracoidea capillaris on Carex boecheriana, Anthracoidea pseudofoetidae on Carex maritima, and Urocystis tothii on Juncus biglumis, are given. Five plant species are reported as new hosts of smut fungi in Greenland, namely, Carex nigra for Anthracoidea heterospora, C. canescens for Anthracoidea karii, C. fuliginosa subsp. misandra for Anthracoidea misandrae, C. maritima for Orphanomyces arcticus, and C. fuliginosa subsp. misandra for Schizonella melanogramma. Three species, Microbotryum violaceum s. str. (recorded as 'Ustilago violacea'), Urocystis anemones, and U. junci, which were previously reported from Greenland, are considered wrongly identified. Additional distribution records are given for 12 species from Greenland: Anthracoidea bigelowii, A. caricis, A. elynae, A. lindebergiae, A. misandrae, A. nardinae, A. rupestris, A. scirpi, Schizonella melanogramma, Stegocintractia hyperborea, Urocystis agropyri, and U. sorosporioides. The most numerous distribution groups are the following: circumpolar-alpine and Arctic-alpine species - 14; circumboreal-polar species - 10; and circumpolar and Arctic species - 6. The most widely distributed smut fungi in Greenland were Anthracoidea bigelowii, A. elynae, Microbotryum bistortarum, and M. vinosum. Most species were found in the High Arctic zone (29 species), while from the Low Arctic zone and the Subarctic zone, 26 and 19 species were known, respectively. Ten species, Anthracoidea bigelowii, A. capillaris, A. elynae, Microbotryum bistortarum, M. koenigiae, M. pustulatum, M. silenes-acaulis, M. vinosum, Schizonella elynae, and Urocystis sorosporioides, were recorded from all three zones. Only plants belonging to six families, Cyperaceae, Poaceae, Juncaceae, Ranunculaceae, Caryophyllaceae, and Polygonaceae, out of a total of 55 in the flora of Greenland, hosted smut fungi. Cyperaceae was the plant family with most host species (23). Carex was the genus with the highest number of host species (22). The total number of the host plants (45 species) was 8.5 % out of a total of 532 vascular plants in the flora of Greenland. A new combination in Carex, C. macroprophylla subsp. subfilifolia, is proposed for Kobresia filifolia subsp. subfilifolia.

The mycological legacy of Elias Magnus Fries.

The taxonomic concepts which originated with or were accepted by Elias Magnus Fries were presented during his lifetime in the printed word, illustrative depiction, and in collections of dried specimens. This body of work was welcomed by the mycological and botanical communities of his time: students and associates aided Fries and after his passing carried forward his taxonomic ideas. His legacy spawned a line of Swedish and Danish mycologists intent on perpetuating the Fries tradition: Hampus von Post, Lars Romell, Seth Lundell and John Axel Nannfeldt in Sweden; Emil Rostrup, Severin Petersen and Jakob Lange in Denmark. Volumes of color paintings and several exsiccati, most notably one edited by Lundell and Nannfeldt attached fungal portraits and preserved specimens (and often photographs) to Fries names. The result is a massive resource from which to harvest the name-concept relationship with clarity. In the 20th century, nomenclatural commissions legislated Fries's Systema and Elenchus as the "starting point" for names of most fungi, giving these books special recognition. The present paper attempts to trace Fries's legacy from his lifetime to the recent past.

Oscillation-induced displacement patterns in a two-dimensional porous medium: a lattice Boltzmann study.

We present a numerical study of the statistical behavior of a two-phase flow in a two-dimensional porous medium subjected to an oscillatory acceleration transverse to the overall direction of flow. A viscous nonwetting fluid is injected into a porous medium filled with a more viscous wetting fluid. During the whole process sinusoidal oscillations of constant amplitude and frequency accelerates the porous medium sideways, perpendicular to the overall direction of flow. The invasion process displays a transient behavior where the saturation of the defending fluid decreases, before it enters a state of irreducible wetting fluid saturation, where there is no net transport of defending fluid toward the outlet of the system. In this state the distribution of sizes of the remaining clusters are observed to obey a power law with an exponential cutoff. The cutoff cluster size is found to be determined by the flow and oscillatory stimulation parameters. This cutoff size is also shown to be directly related to the extracted amount of defending fluid. Specifically, the results show that the oscillatory acceleration of the system leads to potentially a large increase in extracted wetting fluid.

Alignment, clade robustness and fungal phylogenetics- Crepidotaceae and sister families revisited.

The circumscription and delimitation of the agaric family Crepidotaceae and related families in the Agaricales have been analysed using nLSU sequence data and direct optimization. The influence of alignment parameters on clade robustness has been explored, and many clades are found to have a low robustness. Nevertheless, based on clades with a high or moderately high robustness to increased gap costs, a few taxonomic changes are suggested: Crepidotaceae has been amended to include Crepidotus, Episphaeria, Simocybe, Pleuroflammula and Inocybe, the latter genus adding the homoplasious character mycorrhization to the family, Pellidiscus is included in Crepidotus, a position supported by micromorphology, two other genera formerly included in the family, Chromocyphella and Phaeosolenia, are excluded, and a new family, Chromocyphellaceae fam. nov., is erected for them based on fruit body shape, microcharacters, and sequences. Monophyly of Tubariaceae as recently circumscribed was not recovered, but tentatively we accept the genera Tubaria and Phaeomarasmius as members of the family. © The Willi Hennig Society 2009.

Steady-state, simultaneous two-phase flow in porous media: an experimental study.

We report on experimental studies of steady-state two-phase flow in a quasi-two-dimensional porous medium. The wetting and the nonwetting phases are injected simultaneously from alternating inlet points into a Hele-Shaw cell containing one layer of randomly distributed glass beads, initially saturated with wetting fluid. The high viscous wetting phase and the low viscous nonwetting phase give a low viscosity ratio M=10(-4). Transient behavior of this system is observed in time and space. However, we find that at a certain distance behind the initial front a "local" steady-state develops, sharing the same properties as the later "global" steady state. In this state the nonwetting phase is fragmented into clusters, whose size distribution is shown to obey a scaling law, and the cutoff cluster size is found to be inversely proportional to the capillary number. The steady state is dominated by bubble dynamics, and we measure a power-law relationship between the pressure gradient and the capillary number. In fact, we demonstrate that there is a characteristic length scale in the system, depending on the capillary number through the pressure gradient that controls the steady-state dynamics.

Steady-state two-phase flow in porous media: statistics and transport properties.

We study experimentally the case of steady-state simultaneous two-phase flow in a quasi-two-dimensional porous media. The dynamics is dominated by the interplay between a viscous pressure field from the wetting fluid and bubble transport of a less viscous, nonwetting phase. In contrast with more studied displacement front systems, steady-state flow is in equilibrium, statistically speaking. The corresponding theoretical simplicity allows us to explain a data collapse in the cluster size distribution as well as the relation |nablaP| proportional, sqrt[Ca] between the pressure gradient in the system and the capillary number.

Granular labyrinth structures in confined geometries.

Pattern forming processes are abundant in nature. Here, we report on a particular pattern forming process. Upon withdrawal of fluid from a particle-fluid dispersion in a Hele-Shaw cell, the particles are shown to be left behind in intriguing mazelike patterns. The particles, initially being uniformly spread out in a disc, are slowly pulled inwards and together by capillary and pressure forces. Invading air forms branching fingers, whereas the particles are compiled into comparably narrow branches. These branches are connected in a treelike structure, taking the form of a maze. The characteristic length scale within the structure is found to decrease with the volume fraction of the particles and increase with the plate separation in the Hele-Shaw cell. We present a simulator designed to simulate this phenomenon, which reproduces qualitatively and quantitatively the experiments, as well as a theory that can predict the observed wavelengths.

Asian origin and rapid global spread of the destructive dry rot fungus Serpula lacrymans.

The dry rot fungus Serpula lacrymans (Basidiomycota) is the most damaging destroyer of wood construction materials in temperate regions. While being a widespread aggressive indoor biodeterioration agent, it is only found in a few natural environments. The geographical source of spread and colonization by this fungus in human environments is thus somewhat of an enigma. Employing genetic markers (amplified fragment length polymorphisms, DNA sequences and microsatellites) on a worldwide sample of specimens, we show that the dry rot fungus is divided into two main lineages; one nonaggressive residing naturally in North America and Asia (var. shastensis), and another aggressive lineage including specimens from all continents, both from natural environments and buildings (var. lacrymans). Our genetic analyses indicate that the two lineages represent well-differentiated cryptic species. Genetic analyses pinpoint mainland Asia as the origin of the aggressive form var. lacrymans. A few aggressive genotypes have migrated worldwide from Asia to Europe, North and South America and Oceania followed by local population expansions. The very low genetic variation in the founder populations indicate that they have established through recent founder events, for example by infected wood materials transported over land or sea. A separate colonization has happened from mainland Asia to Japan. Our data also indicate that independent immigration events have happened to Oceania from different continents followed by admixture.

Agglomeration of oppositely charged particles in nonpolar liquids.

We study the aggregation of insulating electrically charged spheres suspended in a nonpolar liquid. Regarding the van der Waals interaction as an irreversible sticking force, we are especially interested in the charge distribution after aggregation. Solving the special case of two oppositely charged particles exactly, it is shown that the surface charges either recombine or form a residual dipole, depending on the initial condition. The theoretical findings are compared to numerical results from Monte Carlo simulations.

Molecular phylogenetics suggest a North American link between the anthropogenic dry rot fungus Serpula lacrymans and its wild relative S. himantioides.

The dry rot fungus Serpula lacrymans causes damages in wooden buildings and constructions in temperate regions worldwide. In this study, the global phylogeography of S. lacrymans and its wild relative S. himantioides has been investigated to clarify genealogical relationships and determine the origin and spread of the building strains. Internal transcribed spacer (ITS) nrDNA and parts of the beta-tubulin (tub) and the translation elongation factor (efa) 1a genes were sequenced, and phylogenetic relationships inferred. Some analyses suggest that S. lacrymans may have originated from an ancient S. himantioides lineage, but most results support that S. lacrymans and S. himantioides are monophyletic sister species. Phylogenetic analysis of the ITS data revealed two subgroups within S. lacrymans corresponding to two earlier described varieties; one group occurring frequently in houses worldwide ('Domesticus'), and one group represented by individuals from forests in Northern California ('Shastensis'). A few collections from nature were included in the Domesticus group as well, among other specimens from two newly discovered localities in Far East Russia and Siberia. In the Domesticus group little sequence variation occurs, suggesting a recent worldwide dispersal, possibly linked to human activity. Phylogenetic analyses indicate that the Domesticus group may have originated from an ancient lineage related closely to the Shastensis group. A remarkable shift in morphology and habitat preferences has occurred during the evolution of the Domesticus lineage, linked to the transition from nature to human-made habitats.

Red-capped species of Russula sect. Xerampelinae associated with dwarf scrub.

The microscopic structure of herbarium material of alpine and arctic species of Russula sect. Xerampelinae from Europe and Greenland was studied. Based on our observations two taxa with prevailingly red pilei are accepted from the area: R. subrubens and R. pascua. Other related species occurring in arctic areas are R. cicatricata with a coppery coloured pileus and R. clavipes with a prevailingly greenish olivaceous pileus. As a consequence of the study of type material, R. chamiteae var. chamiteae and R. chamiteae var. microsperma are synonymized with R. subrubens. No European collections could be referred to R. oreina, and accordingly we suggest that this species is absent from Europe.

Relation between pressure and fractional flow in two-phase flow in porous media.

We study average flow properties in porous media using a two-dimensional network simulator. It models the dynamics of two-phase immiscible bulk flow where film flow can be neglected. The boundary conditions are biperiodic, which provide a means of studying steady-state flow where complex bubble dynamics dominate the flow picture. We find fractional flow curves and corresponding pressure curves for different capillary numbers. In particular, we study the case of the two phases having equal viscosity. In this case we find that the derivative of the fractional flow with respect to saturation is related to the global pressure drop. This result can also be expressed in terms of relative permeabilities or mobilities, resulting in an equation tying together the mobilities of the two phases.