Peziza nivalis and relatives-spring fungi of wide distribution.

Several members of the genus Peziza sensu stricto occur at the edge of melting snow. These nivicolous species have been widely reported in the Northern Hemisphere and are also known from Australia and New Zealand. We have used 16 specimens from North America and Australia to study morphology and to perform DNA sequencing. In sequence analyses, we have used ITS1 and ITS2 (internal transcribed spacers), 28S, RPB2 (RNA polymerase II gene), and two genes new to these studies, GAPDH (glyceraldehyde-3-phosphate dehydrogenase) and HSP90 (heat shock protein 90). Although not all regions are available for all samples, we have recognized the following species: Peziza heimii, P. nivalis, and P. nivis. Phylogenetic analyses were done using ITS alone; combined ITS1-5.8S-ITS2, 28S, and RPB2; ITS, and 28S, RPB2, GAPDH, and HSP90. Even with this augmented set of genes and despite their widespread occurrence in North America, Europe, Australia, and New Zealand, we have not definitively distinguished species within this group. To assess these results, pairwise homoplasy index (PHI) analysis was employed. This showed evidence of recombination among the samples of P. nivalis and further supports the view of P. nivalis as a monophyletic cosmopolitan species. As part of this study, we also examined the variation in ITS copies in P. echinospora, for which a genome is available.

Holarctic Species in the Pluteus podospileus Clade: Description of Six New Species and Reassessment of Old Names.

We studied the taxonomy of Pluteus podospileus and similar species using morphological and molecular (nrITS, TEF1-α) data, including a detailed study of the type collections of P. inflatus var. alneus, Pluteus minutissimus f. major, and P. granulatus var. tenellus. Within the P. podospileus complex, we phylogenetically confirmed six species in Europe, five in Asia, and eight in North America. Based on our results, we recognize P. seticeps as a separate species occurring in North America, while P. podospileus is limited to Eurasia. We describe six new species and a new variety: P. absconditus, P. fuscodiscus, P. gausapatus, P. inexpectatus, P. millsii, and P. notabilis and its variety, P. notabilis var. insignis. We elevate Pluteus seticeps var. cystidiosus to species rank as Pluteus cystidiosus. Based on the holotype of P. inflatus var. alneus, collections of P. inflatus identified by Velenovský, and several modern collections, we resurrect the name P. inflatus. Based on molecular analyses of syntypes of Pluteus minutissimus f. major and a holotype of Pluteus granulatus var. tenellus, we synonymize them under P. inflatus. We also increase our knowledge about the morphology and distribution of P. cutefractus.

Holarctic Species in the Pluteus romellii Clade. Five New Species Described and Old Names Reassessed.

We studied the taxonomy of Pluteus romellii, and morphologically similar Holarctic species in the /romellii clade of section Celluloderma, using morphological and molecular data (nrITS, TEF1-α). Pluteus romellii is lectotypified and epitypified and accepted as an exclusively Eurasian species. Pluteus lutescens and P. pallescens are considered synonyms of P. romellii. Pluteus fulvibadius is accepted as a related, but separate, North American species. Five species in the /romellii clade are described as new to science: two from North America (P. austrofulvus and P. parvisporus), one from Asia (P. parvicarpus), one from Europe (P. siccus), and one widely distributed across the Holarctic region (P. vellingae). Basidioma size, pileus color, lamellae color, basidiospore size, hymenial cystidia shape and size, habitat and geographical distribution help separate the species described here, but in some instances only molecular data allows for confident identification. The current status of P. californicus, P. melleipes, P. romellii var. luteoalbus, P. splendidus, P. sternbergii and P.sulphureus is discussed.

The slippery nature of ectomycorrhizal host specificity: Suillus fungi associated with novel pinoid (Picea) and abietoid (Abies) hosts.

Suillus is among the best-known examples of an ectomycorrhizal (ECM) fungal genus that demonstrates a high degree of host specificity. Currently recognized host genera of Suillus include Larix, Pinus, and Pseudotsuga, which all belong to the pinoid clade of the family Pinaceae. Intriguingly, Suillus sporocarps have been sporadically collected in forests in which known hosts from these genera are locally absent. To determine the capacity of Suillus to associate with alternative hosts in both the pinoid and abietoid clades of Pinaceae, we examined the host associations of two Suillus species (S. punctatipes and S. glandulosus) through field-based root tip sampling and seedling bioassays. Root tip collections underneath Suillus sporocarps were molecularly identified (fungi: nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 [ITS barcode]; plant: trnL) to assess the association with multiple hosts. The bioassays contained both single- and two-species treatments, including a primary (Larix or Pseudotsuga) and a secondary (Picea, Pinus, or Abies) host. For the S. punctatipes bioassay, an additional treatment in which the primary host was removed after 8 mo was included to assess the effect of primary host presence on longer-term ECM colonization. The field-based results confirmed that Suillus fungi were able to associate with Abies and Tsuga hosts, representing novel host genera for this genus. In the bioassays, colonization on the primary hosts was detected in both single- and two-species treatments, but no colonization was present when Picea and Abies hosts were grown alone. Removal of a primary host had no effect on percent ECM colonization, suggesting that primary hosts are not necessary for sustaining Suillus colonization once they are successfully established on secondary hosts. Collectively, our results indicate that host specificity is more flexible in this genus than previously acknowledged and help to explain the presence of Suillus in forests where recognized hosts are not present.