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Based on morphology, fungal species have been considered widespread and as a result names of species from Europe or eastern North America were applied to species in western North America. However, DNA sequences have shown that many western taxa are different from their European counterparts; one such case is presented here. Comparisons of ITS and LSU rDNA sequences from ectomycorrhizal root tips and ascomata of specimens identified as Helvella lacunosa from North America, Europe and Asia revealed that the taxa from western North America and Mexico formed a well supported clade different from the eastern North American, European and Asian taxa. Within this western North American clade there are at least four taxa. Here we describe two of these western taxa as new species: Helvella vespertina and Helvella dryophila. Helvella vespertina is a bigger version of H. lacunosa, is variable in hymenial color and shape and forms ectomycorrhizae with conifers; it fruits typically Oct-Jan. Helvella dryophila is characterized by a dark almost black, squat pileus, a light stipe when young, medium size and forms ectomycorrhizae with Quercus species; it fruits Jan-Jun. Due to insufficient material, the two other Helvella taxa are discussed but not formally described here. We also examined the Hypomyces and other mycoparasites associated with the ascomata of Helvella species and discuss misleadingly labeled sequences in public databases. [ABSTRACT FROM AUTHOR]

Abstract: Temperate species of Hypomyces and Cladobotryum that produce the red pigment aurofusarin are common on agaricoid and polyporoid basidiomata of species from five orders of Agaricomycetes. Several cause cobweb disease of commercially cultivated mushrooms resulting in serious losses. We sequenced rpb1, rpb2, tef1, and FG1093 regions in 90 wild strains and 30 strains from mushroom farms, isolated from Europe, North America, Africa, Asia, Australia, and New Zealand. Multigene analyses support the distinctness of five species but reveal Hypomyces rosellus to be paraphyletic, comprising several cryptic lineages. Hypomyces rosellus s. str. is characterised by wide dispersal and gene flow across Eurasia but does not occur in North America. Instead, the lineages from the West and the East Coast appear distinct, having given rise to species inhabiting the Southern Hemisphere. Our results reveal wide misuse of the name H. rosellus, especially for cobweb isolates. The majority of these belong to Hypomyces odoratus, including a weakly supported group of fungicide-resistant strains from Europe and North America sharing identical sequence data. New collections are presented for Cladobotryum rubrobrunnescens and Cladobotryum tenue as well as Cladobotryum multiseptatum and Hypomyces dactylarioides, all previously known only from their type material. The former species pair occurs in Europe and the latter in Australia and New Zealand. Separate lineages appear to be maintained by geographic isolation in North America and temperate Australasia but by host specialisation in the species occurring sympatrically in Europe and Asia. Both specialist and generalist host use strategies have evolved in the group. Although teleomorphs are known in most of the species and unnamed lineages, analyses of the five-gene regions suggest the prevalence of clonal reproduction in H. odoratus. This can be the reason for its success in mushroom farms, also facilitating the spread of fungicide resistance. While tef1 and rpb2 can be recommended for species delimitation, low variation, not exceeding 1 % in the whole ingroup, impeaches the use of ITS as a barcoding gene region in this group of fungi. [Copyright &y& Elsevier]

Fungi in the genus Hypomyces are mycoparasites of various fungal groups. Studies within this genus have dealt primarily with taxonomic descriptions, and no studies have been published on the population biology of these fungi in natural ecosystems. In this study, genetic structure within and among six California (CA) bolete-infecting H. microspermus populations were analyzed with amplified fragment length polymorphism (AFLP). Four of the populations were collected south of the transverse mountain ranges of southern CA, whereas the other populations were from the central coast of CA (Pismo Beach) and from northern CA (Humboldt County). Thirty-nine genotypes were found among 68 isolates based on 30 AFLP markers. This was a higher degree of genotypic diversity than expected because no sexual fruiting bodies were observed in the field, suggesting that sexual reproduction occurs infrequently. These observations were also supported by multilocus disequilibrium analyses. Overall the populations were significantly differentiated (θ = 0.321, P < 0.001), and most population pairwise Fst values were also significantly different. The populations sampled also fit an isolation by distance model based on a Mantel test (P < 0.001). The overall results suggest that this pathogen has a primarily clonal population genetic structure and l(hat spore dispersal was restricted across the sampled populations. [ABSTRACT FROM AUTHOR]

Previous molecular data demonstrated that, although Helicoma is polyphyletic, most species in the genus, including the type Helicoma muelleri, are in the Tubeufiaceae. Here, we use analysis of the small subunit and internal transcribed spacers (ITS) rDNA regions to show that two species, H. monilipes and H. olivaceum, are phylogenetically distant from the type, branching outside of the Tubeufiaceae near Troposporella fumosa in a basal clade of the Dothideomycetes. The phylogeny does not support the recent transfer of T. fumosa to Helicoma. Instead, based on the molecular evidence as well as the examination of cultures and type specimens, Troposporella is reinstated at the generic level, and Helicoma monilipes and Helicoma olivaceum are transferred to Troposporella. All three Troposporella species share the production of helicoid conidia borne on sporodochial conidiomata from blastic conidiogenous cells. A key to accepted species is provided. [ABSTRACT FROM AUTHOR]

Host specificity of the mycoparasite Hypomyces microspermus to the Xerocomus chrysenteron group has been observed, but primarily from European collections. Our objectives were to test host specificity among Hypomyces spp. associated with boletes in California oak-woodlands, investigate population biology of these parasites, and to initiate studies on host-parasite coevolution. Bolete samples were collected from four locations separated by up to 600 km. Hypomyces isolates were cultured and host tissue samples taken for molecular identification. Based on AFLP analysis, four distinct Hypomyces clades were found with little genotypic diversity within each group. ITS-rDNA regions of selected isolates from each group were sequenced and analyzed along with sequences from a previously published phylogeny. Isolates from two AFLP groups clustered with H. microspermus whereas isolates from the other two AFLP groups clustered with H. chrysospermus. ITS-RFLP followed by sequence analysis identified three bolete hosts: (1) X. dryophilus; (2) a Xerocomus species closely related to X. dryophilus with affinities to X. chrysenteron; and (3) a Xerocomus species related to the X. subtomentosus group, which is not closely related to X. dryophilus and X. chrysenteron. H. microspermus infected X. dryophilus and the species with affinities to X. chrysenteron, whereas H. chrysospermus infected the species with affinities to X. chrysenteron and the species related to the X. subtomentosus group. These results support previous observations that H. microspermus is host-specific to the X. chrysenteron group, and that H. chrysospermus is more of a generalist pathogen. We also conclude that host-parasite coevolution studies within this system will not be possible until a phylogeny of North American boletes is in place. [ABSTRACT FROM AUTHOR]

The article reports on the need to conserve W. Nylander's name Spilomium graphideorum with a type based on the lichenicolous fungus alone in order to safeguard the epithet graphideorum and the application of the generic name Milospium D. Hawksw. A description of the Milospium graphideorum, a distinctive dematiaceous hypomycete, is presented.