Vol 10 (2015)

Table of Contents

Articles

Stable isotope evidence for the saprotropic status of the truffle Schenella pityophilus PDF
Chelsea Reha, Darlene Southworth
This research attempts to resolve the mode of nutrition, i.e., saptrtrophic or ectomycorrhizal, for Schenella pityophilus, a sequestrate hypogeous fungus. While a majority of truffles in both the Ascomycota and the Basidiomycota are ectomycorrhizal, S. pityophilus is in the Geastrales in which species are saprotrophic. Stable isotope ratios of C and N have been used to elucidate fungal trophic modes. Stable isotopic ratios of N and C from fruiting bodies of S. pityophilus were compared to those of Rhizopogon species collected from the same sites and known to be ectomycorrhizal. Fruiting bodies of S. pityophilus were depleted in δ15N and enriched in δ13C relative to Rhizopogon species. Stable isotope data support the conclusion that S. pityophilus is saprotrophic rather than mycorrhizal.


Redesignation of Phytophthora taxon Pgchlamydo as Phytophthora chlamydospora sp. nov. PDF
Everett M. Hansen, Paul Reeser, Wendy Sutton, Clive M. Brasier 1-14
A new species, Phytophthora chlamydospora, is described. P. chlamydospora, previously known informally as P. taxon Pgchlamydo, is found in streams and wet soil worldwide and is a pathogen of some riparian tree species. It is self-sterile, and produces persistent non-papillate sporangia, usually on unbranched sporangiophores. Clamydospores are formed most regularly at warmer temperatures. Phytophthora chlamydospora is classified in ITS Clade 6.

 



Bridgeoporus nobilissimus is much more abundant than indicated by the presence of basidiocarps in forest stands PDF
Matthew Gordon, Kelli Van Norman
The polypore Bridgeoporus nobilissimus produces large perennial basidiocarps on large diameter Abies stumps, snags and trees in coniferous forests of the Pacific Northwest.  Despite the size and persistence of the basidiocarps, they are rarely observed, making the conservation of this species a concern.  We determined that a genetic marker for this fungus could be detected in DNA extracted from wood cores taken from trees hosting basidiocarps.  We then tested 105 trees and stumps that did not host B. nobilissimus basidiocarps in plots surrounding B. nobilissimus conks, and 291 trees and stumps in randomly located plots in four stands that contained at least one B. nobilissimus basidiocarp.  We found that trees of all sizes throughout all of the stands hosted B. nobilissimus.  The proportion of Abies trees (live and dead) colonized by B. nobilissimus in these stands ranged from .06 ± .04 in a recently thinned stand to .39 ± .08 in an old growth stand.  The spatial density of B. nobilissimus colonized trees ranged from 25 ± 13 to 61 ± 12 trees/ ha.  The spatial density was highest in the old growth stand, but intermediate in the recently thinned stand.  In a separate study we detected B. nobilissimus DNA in three conifer species that were not known to host this species: Pseudotsuga menziesii, Tsuga heterophylla, and Thuja plicata.  Our results indicate that the survival strategy of this fungus is to produce and maintain a mycelial presence in its hosts while infrequently producing a long-lasting basidiocarp.  The detection of B. nobilissimus, and other fungi adopting this reproductive strategy, is difficult using visual observation, but achievable using methods based on DNA detection of mycelia in hosts.


Puccinia areolata, P. treleasiana, and P. gemella on Marshmarigold (Caltha spp.) in subalpine habitats in Northwestern United States. PDF
Lydia S. Tymon, Dean A. Glawe, Dennis A. Johnson 1-10

Marshmarigolds (Caltha spp.) are members of the buttercup family (Ranunculaceae) and inhabit the Cascade and Rocky Mountains in western North America. Several rust species infect Caltha species, but only Puccinia areolata, Puccinia treleasiana, and Puccinia gemella have been reported in the Pacific Northwest. Observations were made on rust incidence and severity on Caltha spp. in July through September between 2001 and 2013 in subalpine regions of Colorado, Idaho, Montana, Utah, Washington and Wyoming. Leaves, petioles and flower stalks with rust pustules were examined and the host species identified using morphological characteristics. Plants collected in ID, WA, and MT were identified as Caltha leptosepala ssp. howelli (syn Caltha biflora) and plants in WY, CO, and UT were identified as Caltha leptosepala ssp. leptosepala. Foci of infection were typically solitary leaves, individual plants or small clusters of infected plants although a 90% incidence of infected rust plants was observed in a 10 m diameter area with no visually distinct foci in WA in 2013. Puccinia areolata was the only rust observed in Washington, Puccinia gemella was observed in Idaho, and Puccinia treleasiana was observed in Montana and Wyoming. Collections made possible direct comparisons among the three rust species.



Leucoagaricus sabinae (Agaricaceae), a new species from the Dominican Republic PDF
Alfredo Justo, Claudio Angelini, Alberto Bizzi, Alfredo Vizzini 1-15
Leucoagaricus sabinae is proposed as a new species based on material collected in the Dominican Republic. This taxon is characterized macroscopically by the relatively small size, the dull gray-pink pileus, yellow gills immediately turning pink when touched and the ever-present white velar residues on the margin of the pileus. Microscopically the vaguely metachromatic to non-metachromatic spores, the scarce, cylindrical-flexuous cheilocystidia and the piles covering elements with parietal pigment are diagnostic. Based on molecular data (nrLSU, nrITS) this species belongs in the Leucoagaricus/Leucocoprinus clade of the Agaricaceae.


Key to Hawaiian Rosellinia taxa and additions to host-fungus index PDF
J. D. Rogers, Y.-M. Ju 1-4
In the treatment of the Xylariaceae of the Hawaiian Islands (Ju & Rogers, 2012) Rosellinia collections were designated by numbers owing to the uncertainties in identifying them.  The recent publication of a world monograph (Petrini, 2013) has allowed identifications or tentative identifications.  A key to Hawaiian Rosellinia is provided, along with host and collection data.  Additions and corrections to the host-fungus index are likewise provided.


A new species of Phlebopus (Boletales, Basidiomycota) from Mexico PDF
Timothy J. Baroni, Joaquin Cifuentes, Beatriz Ortiz Santana, Silvia Cappello 1-13
A new species, Phlebopus mexicanus, is described from southern tropical rainforests of Mexico based on morphological and molecular characters. Several features distinguish this species from others of Phlebopus including the medium to small basidiomata with olivaceous brown tomentose pileus that becomes finely areolate cracked with age, the dark yellow brown pruina covering most of the stipe, the pale yellow flesh of pileus and stipe that slowly turns blue when exposed, and the lack of hymenial cystidia. Phylogenetic analyses using nLSU sequences support the recognition of this new morphological species in the Sclerodermatineae. Our analyses also suggest that P. portentosus and P. marginatus are not conspecific and relationships of Old World taxa of Phlebopus need further scrutiny. A key to all known New World taxa is provided.