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Species of the ectomycorrhizal (ECM) family Cortinariaceae (Agaricales, Agaricomycetes, Basidiomycota) have long been considered impoverished or absent from lowland tropical rainforests. Several decades of collecting in forests dominated by ECM trees in South America's Guiana Shield is countering this view, with discovery of numerous Cortinariaceae species. To date, ~12 morphospecies of this family have been found in the central Pakaraima Mountains of Guyana. Here, we describe three of these as new species of Cortinarius and two as new species of Phlegmacium from forests dominated by the ECM tree genera Dicymbe (Fabaceae subfam. Detarioideae), Aldina (Fabaceae subfam. Papilionoideae), and Pakaraimaea (Cistaceae). Macromorphological, micromorphological, habitat, and DNA sequence data are provided for each new species.

Chlorosplenium is a small genus comprising five species of inoperculate discomycetes in the order Helotiales (Leotiomycetes) often recognizable by their bright yellowish-green colors and gregarious growth on wood. In this study, we describe five new species- C. aotearoa, C. australiense, C. cusucoense, C. epimorsicum , and C. hawaiiense -based on a combination of recent fieldwork and examination of previously collected fungarium specimens. We use an integrative taxonomic approach to support the distinction of new species, incorporating morphology and DNA sequence data with biogeography. Macro- and micromorphological features of apothecia for all species and culture characteristics for four of the five new species are documented. A multilocus phylogeny based on nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2, partial large subunit nuc ribosomal DNA (28S nuc rDNA), and A-B regions of the largest subunit of RNA polymerase II ( RPB1 ) gene is presented. Additionally, we report Chlorosplenium chlora from Europe for the first time and expand our knowledge of the diversity and distributions of species in this genus in America, Australia, and New Zealand.

South Africa has an indigenous rust (Pucciniales) funga of approximately 460 species. This funga was sampled with species from as many genera as possible. The nuclear ribosomal large subunit (28S) region was amplified from samples representing 110 indigenous species, as well as the small subunit (18S) region and the cytochrome c oxidase subunit 3 (CO3) in some cases, and these were used in phylogenetic analyses. One new species is described, 12 new combinations made, six names reinstated, and two life history connections made. The life histories of this funga were summarized; it is dominated by species with contracted life histories. The majority of species are autoecious, with a small proportion being heteroecious. Of the autoecious species, many will likely be homothallic with no spermagonia. A shortened life history with homothallism allows for a single basidiospore infection to initiate a local population buildup under the prevailing unpredictable climatic conditions. Suggestions are made as to the possible origin of this funga based on the development of the modern South African flora. It is postulated that the rusts of South Africa are of relatively recent origin, consisting of three groups. Firstly, there is an African tropical element with members of the Mikronegerineae ( Hemileia ), the Sphaerophragmiaceae ( Puccorchidium, Sphaerophragmium ), and certain Uredinineae ( Stomatisora ). Their immediate ancestors likely occurred in the tropical forests of Africa during the Paleogene. Secondly, there is a pantropical element including the Raveneliaceae (e.g., Diorchidium, Maravalia, Ravenelia sensu lato, Uropyxis ). This likely diversified during the Neogene, when the mimosoids became the dominant trees of the developing savannas. Thirdly, the Pucciniaceae invaded Africa as this continent pushed northward closing the Tethys Sea. They diversified with the development of the savannas as these become the dominant habitat in most of Africa, and are by far the largest component of the South African rust funga.

The porcini mushroom family Boletaceae is a diverse, widespread group of ectomycorrhizal (ECM) mushroom-forming fungi that so far has eluded intrafamilial phylogenetic resolution based on morphology and multilocus data sets. In this study, we present a genome-wide molecular data set of 1764 single-copy gene families from a global sampling of 418 Boletaceae specimens. The resulting phylogenetic analysis has strong statistical support for most branches of the tree, including the first statistically robust backbone. The enigmatic Phylloboletellus chloephorus from non-ECM Argentinian subtropical forests was recovered as a new subfamily sister to the core Boletaceae. Time-calibrated branch lengths estimate that the family first arose in the early to mid-Cretaceous and underwent a rapid radiation in the Eocene, possibly when the ECM nutritional mode arose with the emergence and diversification of ECM angiosperms. Biogeographic reconstructions reveal a complex history of vicariance and episodic long-distance dispersal correlated with historical geologic events, including Gondwanan origins and inferred vicariance associated with its disarticulation. Together, this study represents the most comprehensively sampled, data-rich molecular phylogeny of the Boletaceae to date, establishing a foundation for future robust inferences of biogeography in the group.

The recent description of the putative fungal pathogen of greenheart trees, Xylaria karyophthora (Xylariaceae, Ascomycota), prompted a study of its secondary metabolism to access its ability to produce cytochalasans in culture. Solid-state fermentation of the ex-type strain on rice medium resulted in the isolation of a series of 19,20-epoxidated cytochalasins by means of preparative high-performance liquid chromatography (HPLC). Nine out of 10 compounds could be assigned to previously described structures, with one compound being new to science after structural assignment via nuclear magnetic resonance (NMR) assisted by high-resolution mass spectrometry (HRMS). We propose the trivial name "karyochalasin" for the unprecedented metabolite. The compounds were used in our ongoing screening campaign to study the structure-activity relationship of this family of compounds. This was done by examining their cytotoxicity against eukaryotic cells and impact on the organization of networks built by their main target, actin-a protein indispensable for processes mediating cellular shape changes and movement. Moreover, the cytochalasins' ability to inhibit the biofilm formation of Candida albicans and Staphylococcus aureus was examined.

The Neotropics have recently emerged as an important region for studies of tropical ectomycorrhizal (ECM) fungi. Specific neotropical areas with high ECM host tree densities have ECM fungal diversities rivaling those of higher-latitude forests. Some forests of the Guiana Shield are dominated by endemic ECM trees of the Fabaceae, including species of Dicymbe (subfam. Detarioideae), Aldina (subfam. Papilionoideae), and Pakaraimaea (Cistaceae). One of the most species-rich ECM fungal families present in each of these systems is Russulaceae. Long-term sampling in forests in Guyana's Pakaraima Mountains has revealed a number of species of the Russulaceae genera Lactarius, Lactifluus , and Russula . In this study, we document a previously unknown, distinct lineage of Lactarius subg. Plinthogalus containing eight species from the Guiana Shield. Here, we describe five of these species from Guyana as new to science: Lactarius humiphilus, Lactarius mycenoides, Lactarius guyanensis, Lactarius dicymbophilus , and Lactarius aurantiolamellatus . Morphological descriptions, habit, habitat, and known distribution are provided for each new species. Sequence data for the barcode internal transcribed spacer (ITS) locus are provided for types and most other collections of the new taxa, and a molecular phylogenetic analysis based on the ITS, 28S, and RPB2 (second-largest subunit of the RNA polymerase II) loci across the genus Lactarius corroborates their morphology-based infrageneric placement. The discovery of this lineage changes our insights into the biogeography and evolutionary history of Lactarius subg. Plinthogalus .

Polydiscidium is an enigmatic, monotypic, and rarely reported genus of Ascomycota of uncertain placement. The morphologically unique Polydiscidium martynii grows on dead wood and forms compound ascomata composed of thick, black, gelatinous somatic tissue that branches out from a common base. Multiple apothecia are located on the branches, mostly toward the tips, and are composed of 8-spored asci and paraphyses embedded in a gelatinous matrix that turns blue in Melzer's reagent. The species was previously known from only three collections from Guyana (holotype), Trinidad, and the Democratic Republic of the Congo and no sequences exist. Due to its peculiar morphology, taxonomic affinities of Polydiscidium have been debated, with different authors having placed it in Helotiaceae, Leotiaceae, or Leotiomycetes incertae sedis. Recent collections of this species resulting from long-term field work in Guyana and Cameroon led us to revisit the morphology and phylogenetic position of this fungus. Newly generated sequences of P. martynii were added to an Ascomycota-wide six-locus data set. The resulting phylogeny showed Polydiscidium to be a member of order Sclerococcales (Eurotiomycetes). Next, a four-locus (18S, ITS, 28S, mtSSU) phylogenetic reconstruction revealed that Polydiscidium is congeneric with Sclerococcum . A new combination is proposed for this species, Sclerococcum martynii . Micromorphological features, including the gelatinous hymenium composed of asci with amyloid gel cap and septate brown ascospores, are in agreement with Sclerococcum . New combinations are proposed for two additional species: Sclerococcum chiangraiensis and S. fusiformis . Finally, Dactylosporales is considered a later synonym of Sclerococcales.

Rust fungi are important plant pathogens and have been extensively studied on crops and other host plants worldwide. This study describes the heterecious life cycle of a rust fungus on Digitaria eriantha (finger grass) and the Solanum species S. lichtensteinii (large yellow bitter apple), S. campylacanthum (bitter apple), and S. melongena (eggplant) in South Africa. Following field observations, inoculation studies involving telial isolates collected from Digitaria plants produced spermogonia and aecia on S. lichtensteinii, S. campylacanthum , and S. melongena . Likewise, inoculation of finger grass with aeciospores collected from the aforementioned Solanum species produced uredinia on D. eriantha. Pennisetum glaucum (pearl millet varieties Milkstar and Okashana, as well as 17 experimental lines) and S. elaeagnifolium (silverleaf nightshade or bitter apple) were resistant to the rust isolates. Morphological descriptions and molecular phylogenetic data confirmed the identity of the rust on Digitaria as P. digitariae , herein reinstated as a species and closely related to P. penicillariae the pearl millet rust, also reinstated. Puccinia digitariae has a macrocyclic, heterecious life cycle in which teliospores overwinter on dormant D. eriantha plants. Aecia sporulate on species of Solanum during spring and early summer to provide inocula that infect new growth of Digitaria .

Four epitypes and three new species of Amanita (Amanitaceae, Agaricales, Agaricomycetes, Basidiomycota) are described from Guineo-Congolian rainforests of Cameroon. Amanita echinulata, A. fulvopulverulenta, A. robusta , and A. bingensis are epitypified based on collections that are the first since the species were described nearly a century ago. Morphological features of the epitypes are described and enumerated. Amanita minima, Amanita luteolamellata , and A. goossensfontanae are described as new and added to the known macromycota of tropical Africa. Habit, habitat, and known distribution are provided for each species. Sequence data for the internal transcribed spacer (ITS) locus are provided for types and other collections of all taxa, and a molecular phylogenetic analysis across the genus Amanita corroborates morphology-based infrageneric placement for each.

This paper describes and illustrates a new species of Laboulbeniales (Ascomycota, Laboulbeniomycetes) recovered from Mastoptera guimaraesi bat flies (Diptera, Streblidae) in Ecuador and Panama. Bat fly-associated Laboulbeniales are still unexplored in the Neotropics, with only four described species of Gloeandromyces and one species of Nycteromyces known. Morphological characteristics and phylogenetic analyses support placement of the new taxon in Gloeandromyces and its recognition as an undescribed species. Gloeandromyces hilleri sp. nov. is easily recognized by 2-3 longitudinal rows of undulations at its perithecial venter. Phylogenetic reconstructions of the large subunit (LSU) ribosomal DNA and the translation elongation factor 1α ( TEF1 ) both resolve G. hilleri and G. nycteribiidarum as sister species. We discuss the utility of LSU and TEF1 as secondary barcodes in Laboulbeniomycetes taxonomy.

In tropical and subtropical rainforests, vegetative fungal rhizomorphs from the Marasmiineae are routinely used as construction material in bird nests. Because rhizomorphs seldom produce mushrooms within nests, the fungal species involved remain largely unknown. In turn, this limitation has prevented us from resolving broader questions such as whether specific fungal species are selected by birds for different functional roles (i.e., attachment, or parasite control). To fill some of these gaps, we collected 74 rhizomorph-containing bird nests from the Neo- and Afrotropics and used nuc rDNA internal transcribed spacer ITS1-5.8S-ITS2 (ITS) sequences to discriminate between rhizomorph-forming species. In total we recovered 25 Marasmiineae species used by birds in nest construction, none of which were shared between the Neotropics and the Afrotropics. We also collected Marasmiineae basidiomes in the vicinity of nests and used ITS sequences to match these sporulating morphs with nest rhizomorphs for nine species. Basidiomes from an additional five species were found fruiting from rhizomorphs incorporated within bird nests. Finally, an additional six species were putatively identified based on publicly available sequence data. Rhizomorphs of five species were found to be utilized almost exclusively as lining material in nests. Lining material comes in direct contact with nestlings and is hypothesized to play a role in parasite control. Rhizomorphs from 10 species were used to attach and anchor nests to substrates; we matched six of those to fruiting litter trap-forming species collected in the understory. Litter traps hold large quantities of fallen litter material, suggesting that birds may preferentially use rhizomorphs that are adapted to bearing heavy loads for nest attachment. Finally, we describe two species of Marasmius-M. neocrinis-equi , sp. nov., and M. nidus-avis , sp. nov.-that are commonly found associated with bird nests and show that rhizomorph production is common across the genus.

Rust disease was observed on populations of Suaeda californica near Morro Bay, California. The pathogen was identified as a species of Uromyces based on teliospore and urediniospore morphology and nuc 28S rDNA sequence analysis. The isolate was compared with previously described species of Uromyces that infect members of Chenopodiaceae, prompting a taxonomic reevaluation of Uromyces species on Suaeda . Herein, Uromyces rebeccae is described. It can be differentiated from the closely related U. chenopodii (syn.: Aecidium chenopodii-fruticosi; U. giganteus ) based on host range, teliospore morphology, and 28S sequence data. The new combination, Uromyces chenopodii-fruticosi , is made for Aecidium chenopodii-fruticosi , the oldest name for Eurasian Suaeda rust. Finally, it was determined that U. giganteus likely does not occur in the United States and that the rust of S. taxifolia in the United States likely comprises a third, yet unnamed taxon, different from both U. rebeccae and U. chenopodii-fruticosi . This is the first record of a rust fungus on S. californica . An identification key for Uromyces species reported on Chenopodiaceae is provided.

We report on the discovery and characterization of a novel Fusarium species that produced yellow-orange pseudoflowers on Xyris spp. (yellow-eyed grass; Xyridaceae) growing in the savannas of the Pakaraima Mountains of western Guyana. The petaloid fungal structures produced on infected plants mimic host flowers in gross morphology. Molecular phylogenetic analyses of full-length RPB1 (RNA polymerase largest subunit), RPB2 (RNA polymerase second largest subunit), and TEF1 (elongation factor 1-α) DNA sequences mined from genome sequences resolved the fungus, described herein as F. xyrophilum , sp. nov., as sister to F. pseudocircinatum within the African clade of the F. fujikuroi species complex. Results of a polymerase chain reaction (PCR) assay for mating type idiomorph revealed that single-conidial isolates of F. xyrophilum had only one of the MAT idiomorphs ( MAT1-1 or MAT1-2 ), which suggests that the fungus may have a heterothallic sexual reproductive mode. BLASTn searches of whole-genome sequence of three strains of F. xyrophilum indicated that it has the genetic potential to produce secondary metabolites, including phytohormones, pigments, and mycotoxins. However, a polyketide-derived pigment, 8- O -methylbostrycoidin, was the only metabolite detected in cracked maize kernel cultures. When grown on carnation leaf agar, F. xyrophilum is phenotypically distinct from other described Fusarium species in that it produces aseptate microconidia on erect indeterminate synnemata that are up to 2 mm tall and it does not produce multiseptate macroconidia.

The genus Bannoa consists of four described species associated with dead leaves in southwestern Japan. In this study, we describe three new species, Bannoa guamensis, B. rosea , and B. tropicalis , from the South Pacific island of Guam and Guyana in South America. Isolates were obtained from surfaces of diseased and healthy leaves of plants in the Euphorbiaceae, Asteraceae, and Poaceae. DNA sequences from four gene regions, including nuc rDNA internal transcribed spacer ITS1-5.8S-ITS2 (ITS), D1-D2 domains of nuc 28S rDNA (28S), nuc 18S rDNA (18S), and a portion of tef1 , which encodes translation elongation factor 1-alpha, were produced for phylogenetic analysis. Intercompatibility tests were performed, and subsequent development of clamp connections and basidia were documented for B. tropicalis . Potential life history strategies and association with diseased leaves, including rust-infected leaves, were evaluated across the genus. This is the first report of a species of Bannoa from South America.

In 2010-2011, a Xylaria sp. was documented growing from seeds of both Chlorocardium rodiei and Chlorocardium venenosum, a commercially valuable timber in Guyana. We conducted extensive surveys in 2015-2016, where this Xylaria sp. was observed fruiting from ca. 80% of dispersed seeds in both natural and logged forests in the Upper Demerara-Berbice, Potaro-Siparuni, and the Cuyuni-Mazaruni districts of central Guyana. Species of Xylaria are ascomycetous fungi generally characterized by black, carbonaceous, multiperitheciate ascoma commonly found growing on dead wood. Combined teleomorphic and molecular data indicate that the fungus represents a novel species, described here as Xylaria karyophthora.

Carotenoid-containing yeasts in Sporidiobolales (Microbotryomycetes, Pucciniomycotina, Basidiomycota) have been reported from contrasting ecosystems, including marine, soil, phylloplane, polar ice, and many others. Here, we present several analyses drawing on 583 new isolates collected from various substrates around the globe and publicly available sequences from numerous published environmental studies. We provide a multilocus phylogenetic reconstruction of the order, estimates for total species richness, a snapshot of global distribution patterns, and analysis of niche preferences in Sporidiobolales, emphasizing their occurrence in commercial crops and food products. We evaluated loci commonly used in fungal phylogenetics, finding that RNA polymerase II subunits 1 and 2 (RPB1, RPB2) are of little utility in this group. We have reconfirmed the monophyly of Sporidiobolales with three well-supported genera, which are, in descending order of number of species, Rhodotorula, Sporobolomyces, and Rhodosporidiobolus. From our data, we estimate ca. 260 species in Sporidiobolales, of which 42 are described, and ca. 52,000 species in Pucciniomycotina. The majority of data regarding Sporidiobolales are from North America and Europe, highlighting severe knowledge gaps for most of South and Central America and Africa.

Sterile fungal isolates are often recovered in leaf and root endophytic studies, although these seldom play a significant role in downstream analyses. The authors sought to identify and characterize two such endophytes-one representing the most commonly recovered fungal isolate in recent studies of needle endophytes of Pinus taeda and the other representing a rarely isolated root endophyte of Populus trichocarpa. Both are shown by DNA sequencing to be undescribed species of Atractiellomycetes (Pucciniomycotina, Basidiomycota), a poorly characterized class of mostly plant-associated and presumably saprobic microfungi. The authors describe the new genus and species Atractidochium hillariae (Phleogenaceae) and the new species Proceropycnis hameedii (Hoehnelomycetaceae), both in the Atractiellales, to accommodate these unusual isolates. Following incubations of 1-2 mo, A. hillariae produces minute white sporodochia, similar to those produced by several other members of Atractiellales, whereas Pr. hameedii forms conidia singly or in chains in a manner similar to its sister species Pr. pinicola. Additionally, we provide a taxonomic revision of Atractiellomycetes based on multilocus analyses and propose the new genera Neogloea (Helicogloeaceae) and Bourdotigloea (Phleogenaceae) to accommodate ex-Helicogloea species that are not congeneric with the type H. lagerheimii. Atractiellomycetes consists of a single order, Atractiellales, and three families, Hoehnelomycetaceae, Phleogenaceae, and Helicogloeaceae. Accumulated evidence suggests that Atractiellomycetes species are common but infrequently isolated members of plant foliar and root endobiomes.

Among fungi isolated from healthy root mycobiomes of Populus, we discovered a new endorrhizal fungal species belonging to the rust lineage Pucciniomycotina, described here as Atractiella rhizophila. We characterized this species by transmission electron microscopy (TEM), phylogenetic analysis, and plant bioassay experiments. Phylogenetic sequence analysis of isolates and available environmental and reference sequences indicates that this new species, A. rhizophila, has a broad geographic and host range. Atractiella rhizophila appears to be present in North America, Australia, Asia, and Africa and is associated with trees, orchids, and other agriculturally important species, including soybean, corn, and rice. Despite the large geographic and host range of this species sampling, A. rhizophila appears to have exceptionally low sequence variation within nuclear rDNA markers examined. With inoculation studies, we demonstrate that A. rhizophila is nonpathogenic, asymptomatically colonizes plant roots, and appears to foster plant growth and elevated photosynthesis rates.

A new Asian species of Crepidotus (Basidiomycota, Agaricales), C. asiaticus, is presented based on morphological and nuc rDNA internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) and large subunit (28S) sequence data. This new species, found in India and Thailand, is characterized by the centrally stipitate medium-sized basidiomata, orange to reddish brown pileus, white to brownish orange lamellae, and white stipe. Based on morphology, C. asiaticus is similar to the neotropical C. thermophilus. However, the microscopic characters, especially the size and shape of the basidiospores, can be used to distinguish these two taxa, as well as their geographic distributions. Further, the phylogenetic position of C. asiaticus is unique based on ITS and 28S nuc rDNA sequences. Melanomphalia argipoda, described by Singer from Ecuador, is also a stipitate Crepidotus based on an ITS sequence of the type specimen, so the new combination is proposed here. Phylogenetically, the three species form a monophyletic group with the Asiatic C. asiaticus forming the sister lineage to the neotropical C. argipodus and C. thermophilus.

Early diverging taxa of Ascomycota and Basidiomycota share similarities in subcellular characters of the spindle pole body (SPB), nuclear division, and septal pore apparatus, but our understanding of character evolution is incomplete because of the limited number of structural studies within the earliest diverging subphyla of Dikarya, Taphrinomycotina and Pucciniomycotina. Two species of Helicogloea (Atractiellomycetes) were analyzed for these characters and provide data on SPB and nuclear division for an additional class of Pucciniomycotina. A detailed analysis of septal pore apparatus for the Helicogloea species permits comparisons with those of other Pucciniomycotina and Ascomycota. The endogenous origin of hyphal branches is shown to occur in a third class of Pucciniomycotina. The full set of characters supports a close relationship between Atractiellomycetes and Pucciniomycetes.

Binderoboletus segoi gen. and sp. nov., Guyanaporus albipodus gen. and sp. nov. and Singerocomus rubriflavus gen. and sp. nov. (Boletaceae, Boletales, Basidiomycota) are described from the Pakaraima Mountains and adjacent lowlands of Guyana. Xerocomus inundabilis, originally described from the central Brazilian Amazon and based solely on the type collection, is redescribed from numerous collections from Guyana and transferred into Singerocomus. These boletes occur in Neotropical forests dominated by ectomycorrhizal trees in the genera Dicymbe (Fabaceae subfam. Caesalpinioideae), Aldina (Fabaceae subfam. Papilionoideae) and Pakaraimaea (Dipterocarpaceae). Three of the species were repeatedly found in a multiyear sporocarp survey in Dicymbe corymbosa-monodominant forest. Macromorphological, micromorphological, habitat and multilocus DNA sequence data are provided for each species. A molecular phylogenetic analysis based on a large taxon set across the Boletaceae justifies erection of the new genera., (© 2016 by The Mycological Society of America.)

Numerous strains of a novel yeast were isolated in Louisiana, USA, from the leaves of several palustrine plants, most frequently from the invasive aquatic ferns Salvinia minima and S. molesta. This fungus produced fast-growing colonies that were grayish violet to dark blue in culture and rapidly reproduced via production of copious ballistoconidia that germinated to form pseudohyphae. Colonies produced many two-celled yeasts that were distinctly hourglass-or peanut-shaped, and occurred singly or in chains. Phylogenetic analyses of translation elongation factor 1-α, β-tubulin and the nuc rDNA regions encompassing 28S D1-D2 domains, 18S and the internal transcribed spacers 1 and 2, including 5.8S, indicate this fungus is a member of Ustilaginomycetes but holds an isolated position, distinct from the two currently recognized orders, Ustilaginales and Urocystales. Here we describe Violaceomycetales ord. nov., Violaceomycetaceae fam. nov. and Violaceomyces palustris gen. et sp. nov. for this unusual fungus., (© 2015 by The Mycological Society of America.)

Craterellus olivaceoluteus sp. nov. and Craterellus cinereofimbriatus sp. nov. are described as new to science. These fungi were collected from Guyana in association with ectomycorrhizal host trees in the genera Dicymbe (Fabaceae subfam. Caesalpinioideae) and Pakaraimaea (Dipterocarpaceae). Cantharellus guyanensis Mont., originally described from French Guiana, is redescribed from recent collections from Guyana, with additional range extensions for the species provided based on material examined from French Guiana, Venezuela, and north central, northeastern and southern Brazil, circumscribing nearly the entire Guiana Shield region and beyond. A new distribution record from French Guiana is provided for Craterellus excelsus T.W. Henkel & Aime. Macromorphological, micromorphological and habitat data are provided for the new species and C. guyanensis as well as DNA sequence data from the nuclear ribosomal regions of the internal transcribed spacer (ITS) and 28S large subunit (LSU); additional sequence data is provided for C. guyanensis and C. excelsus specimens collected outside Guyana. The relationships of these taxa within the Cantharellaceae were evaluated with phylogenetic analyses of ITS and LSU sequence data. This work brings the total number of Cantharellaceae species known from Guyana to eight. A key to the Cantharellus and Craterellus species known from the lowland Neotropics and extralimital montane Central and South America is provided.

A field survey of ballistosporic yeasts in a Neotropical forest yielded a new species isolated from a fern leaf. The isolate is a cream-colored butyrous yeast that reproduces by budding. Budding occurs at both the apical and basal cell poles; occasionally multiple budding events co-occur, giving rise to rosette-like clusters of cells at both poles of the yeast mother cell. DNA sequences of large and small subunit and the internal transcribed spacer regions of the nuclear ribosomal DNA cistron indicated an affinity to Microbotryomycetes, Pucciniomycotina. A new genus, Meredithblackwellia, is proposed to accommodate the new species, M. eburnea (type strain MCA4105). Based on phylogenetic analyses, Meredithblackwellia is related to Kriegeria eriophori, a sedge parasite, to an aquatic fungus Camptobasidium hydrophilum and to several recently described anamorphic yeasts that have been isolated from plant material or psychrophilic environments. Morphological and ultrastructural studies confirm the relatedness of M. eburnea to these taxa and prompted the re-evaluation of higher-level classification within Microbotryomycetes. We propose here a new order, Kriegeriales, and place two families, Kriegeriaceae fam. nov. and Camptobasidiaceae R.T. Moore, within it. Our study re-emphasizes the need for systematic revision of species described in Rhodotorula.

Members of the Cantharellaceae (Cantharellales, Basidiomycota) are common ectomycorrhizal associates of the leguminous genus Dicymbe in the Pakaraima Mountains of Guyana. Eight distinct species or morphospecies currently are recognized in Craterellus Pers. or Cantharellus Adans. ex Fr. from Guyanese Dicymbe-dominated forests. We evaluated the systematics of these taxa with phylogenetic analyses of DNA sequence data from the nuclear ribosomal regions of the internal transcribed spacer (ITS) and 28S large subunit (LSU). The results of these analyses along with careful assessment of morphology let us described two new species, Craterellus atratoides sp. nov. and Craterellus strigosus sp. nov., redescribe Craterellus atratus (Corner) Yomyart et al. based on new material from Guyana, and propose a new combination in Craterellus for Cantharellus pleurotoides T.W. Henkel, Aime & S.L. Mill. Macroscopic illustrations are provided for two additional cantharelloid morphospecies confirmed in Craterellus, as well as the regionally endemic Cantharellus guyanensis Mont. Macromorphological, micromorphological and habitat data are provided for C. atratoides, C. strigosus and C. atratus, and ITS and LSU sequence data are provided for each of the eight known Guyanese taxa.

Elaphomyces compleximurus sp. nov. and E. digitatus sp. nov. are described from the Pakaraima Mountains of Guyana. Macromorphological, micromorphological, habitat and DNA sequence data are provided for each new species. This is the first report of Elaphomyces ascomata associated with ectomycorrhizal members of the Fabaceae and also for the genus from the lowland South American tropics.

Mayapple rust is a common, disfiguring disease that is widespread in temperate eastern North America wherever the host, Podophyllum peltatum, occurs. Puccinia podophylli, the etiological agent of this rust, has been shown to be distantly related to both Puccinia and Uromyces as exemplified by their types. A systematic study was made to determine the generic classification of P. podophylli. Phylogenetic analyses of two rDNA loci from multiple specimens support the recognition of this taxon as a separate genus of Pucciniaceae. Based on historical literature and type material, P. podophylli was found to represent the type of the forgotten genus Allodus and it is correctly named Allodus podophylli. A neotype is designated for Puccinia podophylli Schwein. (≡ Allodus podophylli) and a lectotype is designated for Aecidium podophylli.

Three new species of Clavulina (Cantharellales, Basidiomycota) are described from rainforests dominated by ectomycorrhizal trees of the leguminous genus Dicymbe (Fabaceae subfam. Caesalpinioideae) from the central Guiana Shield. Species of Clavulina typically form branched, coralloid basidiomata with amphigenous hymenia. However, the three species described here form resupinate or effuso-coralloid basidiomata, macromorphological forms previously unknown in Clavulina. Macromorphological, micromorphological, habitat and DNA sequence data are provided for each new species. Micromorphological features and DNA sequence data from the second largest subunit of DNA-dependant RNA polymerase II (rpb2) and internal transcribed spacer (ITS) and large subunit (28S) of the ribosomal repeat justify placement of these new species in Clavulina. Comparisons with described Clavulina species and other resupinate taxa within the Cantharellales are provided.

Frommeëlla (Phragmidiaceae, Pucciniales, Basidiomycota), which currently includes two species and is typified by F. tormentillae, causes rust on members of tribe Potentilleae (Rosaceae). The genus has been distinguished from Phragmidium on the basis of having only one germ pore per teliospore cell rather than two or three and by aecial characters. Phylogenetic analyses of both currently accepted Frommeëlla spp. with nLSU rDNA data suggest that Frommeëlla was derived from within a clade representing Phragmidium. Thus Frommeëlla should be considered to be a later generic synonym of Phragmidium. Analyses also indicate that Frommeëlla tormentillae on Potentilla species includes two taxa recognized herein as Phragmidium potentillae-canadensis and P. tormentillae. Frommeëlla mexicana on Potentilla spp. formerly classified in Duchesnea, is distinct from but sister to the other two species. Based on data regarding type specimens that were presented in a study by McCain and Hennen, the new combination Phragmidium mexicanum is proposed as the correct name for this species. Necessary studies of original material were made, and Phragmidium potentillae-canadensis is lectotpyified and epitypified. Although considered and expanded here, further examination of species boundaries and host ranges of the fungi formerly classified in Frommeëlla is warranted.

Based on multiple gene analyses (nuclear large subunit, nuclear small subunit, internal transcribed spacer region including the 5.8 s subunit rDNA, and translation elongation factor 1α) and septal pore ultrastructure we describe a new lineage of Pucciniomycotina consisting of a new class, Tritirachiomycetes, new order, Tritirachiales, and new family, Tritirachiaceae. Tritirachium dependens, T. oryzae, T. roseum (reintroduced), T. cinnamomeum and two unidentified species are recognized. Phylogenetic analyses do not support existing morphological circumscription of some species, and the available evidence suggests that morphological evaluation alone is not adequate for species identification.

In North America Melampsora rusts that parasitize willows (Salix species) have never been adequately studied and mostly have been referred to a collective species, Melampsora epitea (Kunze & Schm.) Thüm, of European origin. Even taxa that are nominally distinct from M. epitea, such as M. abieti-caprearum and M. paradoxa, currently are considered to be "races" of M. epitea. Within the range of our field surveys and collections in the Pacific Northwest and the Southwest only two species of Melampsora thus were expected: M. epitea (including its races) and M. ribesii-purpureae. In this study of Melampsora on 19 species of Salix in the western United States 14 phylogenetic species, or phylotypes, were apparent from nuclear rDNA sequencing of 140 collections or isolates. Our collections of the races of M. epitea, M. abieti-caprearum and M. epitea f. sp. tsugae belonged to one phylotype, termed lineage 'N'. Assuming that M. ribesii-purpureae represents one other phylotype, 12 phylotypes still are unaccounted for by current taxonomy. Moreover Eurasian M. ribesii-purpureae was not closely related to any of the phylotypes reported here. Even more problematic was the resistance of Eurasian species of Salix, including the type host of M. epitea, S. alba, to North American Melampsora, including phylotype 'N', in both the field and in inoculation experiments. These results suggest the need for the description of many new species of Melampsora on Salix in western North America. Additional analyses presented here might guide further research in this direction.

A new species of Cantharocybe, C. brunneovelutina, is described and illustrated from the Orange Walk District of Belize. The species is characterized by the subvelutinous brown pileus, brownish gray stipe and microscopically by cheilocystidia that have prong-like appendages. Analysis of nLSU rDNA sequences relates this species to Cantharocybe gruberi, the sole member of a previously monotypic genus of uncertain placement. We also provide a microscopic description and illustrations of the type collection of Cantharocybe gruberi and compare the two species. Morphological comparisons among Cantharocybe and its sister genus, Cuphophyllus (= Camarophyllus), and allied genera are discussed.

Two new species of Clavulina Schroet. (Clavulinaceae, Cantharellales, Basidiomycota) and new distribution records for Clavulina amazonensis Corner and Clavulina sprucei (Berk.) Corner are described from the Pakaraima Mountains of Guyana, in the central Guiana Shield region. These fungi occur in rainforests dominated by ectomycorrhizal (ECM) trees of the leguminous genus Dicymbe (Fabaceae subfam. Caesalpinioideae). Macromorphological, micromorphological and habitat data are provided for each species. Nuclear ribosomal DNA sequences of the internal transcribed spacer region and 28S subunit were obtained for new species and from representative collections of C. amazonensis and C. sprucei. The two new species, Clavulina kunmudlutsa sp. nov. and Clavulina tepurumenga sp. nov., constitute important edible fungi for the Patamona Amerindians. Our specimens of C. sprucei represent the first reports of the species since 1853 as well as a range extension of nearly 1500 km, while sequence data from basidiomata as well as ECM roots suggest that this taxon consists of a cryptic species complex.

This paper is the fourth in a series documenting the Entolomataceae taxa (Agaricales, Basidiomycota) from Guyana. Six new species in three genera are described-Calliderma caeruleosplendens, Paraeccilia unicolorata, Trichopilus tibiiformis, T. fasciculatus, T. vividus, and T. luteolamellatus-occurring primarily in mixed tropical rainforests of the Potaro River Basin in the Pakaraima Mountains. Macromorphological, micromorphological and habitat data are provided for each. None of these genera had been reported from Guyana.

Russian knapweed (Rhaponticum repens) is a rangeland weed pest in the western United States. One candidate fungus for biological control of R. repens is Puccinia acroptili, which causes a rust disease. Understanding the life cycle of candidate rust fungi for weed biological control is an essential component in risk assessments and evaluations, and for P. acroptili such was unknown. For this reason greenhouse studies were undertaken to clarify the life cycle of P. acroptili under artificial conditions. Spermogonia with spermatia developed on R. repens following plant inoculation with teliospores. Artificial transfer of spermatia between spermogonia resulted in the development of aecia with uredinioid aeciospores. Inoculation with aeciospores or urediniospores resulted in uredinia containing urediniospores and occasional amphispores. Telia with teliospores and occasional mesospores developed later. Teliospores produced typical basidia with four basidiospores. These results suggest that the life cycle of P. acroptili is macrocyclic and autoecious. Inoculation with teliospores also frequently resulted in production of sori that were morphologically similar to aecia but which were not associated with spermogonia or the classical transfer of spermatia. The ontology of these sori is unknown. This is the first description of spermogonia and the first report and description of basidiospores, aecia, aeciospores, amphispores and mesospores of P. acroptili.

This paper constitutes the first documented accounts of Entolomataceae taxa (Agaricales, Basidiomycota) from Guyana. Entoloma olivaceocoloratum, Entoloma rugosostriatum, Entoloma fragilum and Entoloma illinita are described as new species from the Pakaraima Mountains, occurring in rainforests dominated by ectomycorrhizal Dicymbe and Aldina spp. Macromorphological, micromorphological and habitat data are provided for the new species.

An overview of the phylogeny of the Agaricales is presented based on a multilocus analysis of a six-gene region supermatrix. Bayesian analyses of 5611 nucleotide characters of rpb1, rpb1-intron 2, rpb2 and 18S, 25S, and 5.8S ribosomal RNA genes recovered six major clades, which are recognized informally and labeled the Agaricoid, Tricholomatoid, Marasmioid, Pluteoid, Hygrophoroid and Plicaturopsidoid clades. Each clade is discussed in terms of key morphological and ecological traits. At least 11 origins of the ectomycorrhizal habit appear to have evolved in the Agaricales, with possibly as many as nine origins in the Agaricoid plus Tricholomatoid clade alone. A family-based phylogenetic classification is sketched for the Agaricales, in which 30 families, four unplaced tribes and two informally named clades are recognized.

In this study we provide a phylogenetically based introduction to the classes and orders of Pucciniomycotina (= Urediniomycetes), one of three subphyla of Basidiomycota. More than 8000 species of Pucciniomycotina have been described including putative saprotrophs and parasites of plants, animals and fungi. The overwhelming majority of these (approximately 90%) belong to a single order of obligate plant pathogens, the Pucciniales (= Uredinales), or rust fungi. We have assembled a dataset of previously published and newly generated sequence data from two nuclear rDNA genes (large subunit and small subunit) including exemplars from all known major groups in order to test hypotheses about evolutionary relationships among the Pucciniomycotina. The utility of combining nuc-lsu sequences spanning the entire D1-D3 region with complete nuc-ssu sequences for resolution and support of nodes is discussed. Our study confirms Pucciniomycotina as a monophyletic group of Basidiomycota. In total our results support eight major clades ranked as classes (Agaricostilbomycetes, Atractiellomycetes, Classiculomycetes, Cryptomycocolacomycetes, Cystobasidiomycetes, Microbotryomycetes, Mixiomycetes and Pucciniomycetes) and 18 orders.

The two most devastating diseases of cacao (Theobroma cacao)--the source of chocolate--in tropical America are caused by the fungi Crinipellis perniciosa (witches' broom disease) and Moniliophthora roreri (frosty pod rot or moniliasis disease). Despite the agricultural, socio-economic and environmental impact of these fungi, most aspects of their life cycles are unknown, and the phylogenetic relationships of M. roreri have yet to be conclusively established. In this paper, extensive phylogenetic analyses of five nuclear gene regions (28S rDNA, 18S rDNA, ITS, RPB1, and EF1-alpha) confirm that C. perniciosa and M. roreri are sister taxa that belong in the Marasmiaceae (euagarics). Furthermore, these taxa form part of a separate and distinct lineage within the family. This lineage includes the biotrophic fungi Moniliophthora perniciosa comb. nov. and M. roreri, as well as one undescribed endophytic species. The sister genera to Moniliophthora are Marasmius, Crinipellis and Chaetocalathus, which consist mainly of saprotrophic litter fungi.

During fieldwork in Guyana several unusual and distinctive taxa of polypores were collected, three of which are described here as new. The first of these, Amauroderma coltricioides is the first species known in the Ganodermataceae with smooth basidiospores. Coltricia verrucata and Coltriciella navispora also are described as new, and a key to the neotropical species of Coltricia is provided. Finally, a checklist of 73 poroid fungi from Guyana is given, of which 29 are new records for the country.

Melanomphalia thermophila (Sing.) Sing. is a rarely collected agaric previously known only from Florida and Brazil. This taxon was originally described as a species of Tubaria and much of Singer's rationale for placing Tubaria within the Crepidotaceae (Imai) Sing. was based on anatomical similarities between T. thermophila and Crepidotus (Fr.) Staude. In later works, T. thermophila was transferred to Melanomphalia M.P. Christ., again forming the basis upon which Singer placed Melanomphalia within the Crepidotaceae. Based on examination of newly collected specimens from Puerto Rico and Panama, type studies, and nuclear large subunit rDNA analysis, we conclude that this taxon is, in fact, a centrally stipitate Crepidotus. Melanomphalia thermophila is transferred to Crepidotus, fully described and illustrated.

Study of the genus Gomphidius from recent material from Asia and North America has been carried out using traditional taxonomy combined with molecular systematics. Two new species of Gomphidius (G. borealis and G. pseudoflavipes) are described, one from Eastern Siberia and a second from rarely collected habitats in the Western United States. One taxon has the longest spores reported for the genus and the second species appears to be associated with a Siberian larch.

Morphological and habitat descriptions, illustrations and taxonomic discussions are presented for two newly described species of pleurotoid Lactarius, L. brunellus and L. multiceps, from the Pakaraima Mountains of Guyana. A third species, L. igapoensis, is synonymized with L. panuoides.