Steven Miller

University of Wyoming | UW · Botany

Premise: Mycoheterotrophic plants rely on fungi to obtain their carbon requirements. Recent experiments demonstrated the presence of endophytic bacteria associated with mycoheterotrophs. Although mycoheterotrophs show high specificity for their fungal partners, it is not known whether associated bacteria do so also or if they may have a definite f...

Fairy rings are conspicuous features of the Laramie Basin of southeastern Wyoming. Ten fairy ring sites chosen for intensive study were located using a small plane and 415 whole and partial fairy rings were georeferenced and ground-truthed. Fairy ring forming fungi were identified using a combination of taxonomy and ITS fungal barcode sequence comp...

Yosemite National Park has hundreds of historic apple trees that were planted within orchards in the 1800s. In preparation for updating and finalizing an Orchard Management Plan to evaluate their significance, park managers partnered with the USDA-ARS to assign cultivar names to trees, where possible. Herein, 361 of Yosemite's apple trees were geno...

Apples (Malus x domestica) played a significant role in America’s westward expansion. Heritage apple trees can still be found in old orchard plantings and abandoned homesteads that were established during the 19th and early 20th centuries. In Wyoming, there are reports of 29 cities where apples were grown from the beginning (1870) to the rapid decl...

Apple trees have been grown in Wyoming since at least the 1870s. The largest orchards produced apples for market sales, rootstock trees for local residents, and even developed new cultivars that improved yield and performance under Wyoming’s cold and drought- prone conditions. For example, Lander, or “Apple City,” at one time had over 4,700 trees d...

Thousands of apple trees were planted in Wyoming’s orchards and homesteads in the 1800s, many of which are still alive today. Unfortunately, cultivar identity of these trees has mostly been lost or obscured. The purpose of this research was to identify heritage apple cultivars in Wyoming using genetic fingerprinting (microsatellite) techniques and...

The purpose of this research was to identify heritage apple cultivars in Wyoming using genetic fingerprinting (microsatellite) techniques and to use this information to make recommendations on candidate cold-hardy cultivars for specialty crop and breeding programs.

Our objectives are to (1) investigate the use of molecular genotyping techniques to identify heirloom, historic, and novel apple cultivars in approximate 100-year-old orchards in Wyoming; and (2) establish a germplasm repository orchard at ShREC.

Amanita ballerina and A. brunneitoxicaria spp. nov. are introduced from Thailand. Amanita fuligineoides is also reported for the first time from Thailand, increasing the known distribution of this taxon. Together, those findings support our view that many taxa are yet to be discovered in the region. While both morphological characters and a multipl...

Phylogenetic tree inferred by Maximum Likelihood analysis of β-tubulin sequences. Bootstrap values (BS) ≥70% are shown above the branches. Amanita species with sequences generated in this study are highlighted in bold. Voucher collection identifiers are provided after each species name. (EMF)

Phylogenetic tree inferred by Maximum Likelihood analysis of rpb2 sequences. Bootstrap values (BS) ≥70% are shown above the branches. Amanita species with sequences generated in this study are highlighted in bold. Voucher collection identifiers are provided after each species name. (EMF)

Phylogenetic tree inferred by Maximum Likelihood analysis of ITS1+5.8S+ITS2 sequences. Bootstrap values (BS) ≥70% are shown above the branches. Amanita species with sequences generated in this study are highlighted in bold. Voucher collection identifiers are provided after each species name. (EMF)

The mycoheterotrophic plant Pterospora andromedea is an important species in understanding the evolution and ecology of highly specialized plant-fungal symbioses. Lineages within P. andromedea have been shown to engage in highly specific interactions with obligate fungal associates found in Rhizopogon subgenus Amylopogon. Unfortunately, evidence of...

Rhizopogon species are ecologically significant ectomycorrhizal fungi in conifer ecosystems. The importance of this system merits the development and utilization of a more robust set of molecular markers specifically designed to evaluate their evolutionary ecology. Anonymous nuclear loci (ANL) were developed for R. subgenus Amylopogon. Members of t...

Lepista sordida is an edible and medicinal mushroom, but until now it had to be collected from the wild. The present study is the first report of the successful cultivation of a wild strain of L. sordida from Thailand. The morphological description and molecular examination of the fungus are included, in order to confirm the identification of the s...

Mushrooms belonging to the genus Amanita were collected during a fungal biodiversity study in northern Thailand in 2012–2014. Morphological characteristics and molecular phylogenetic analyses were used to identify the mushrooms to species. Amanita castanea is described as new to science and compared with phenetically and phylogenetically similar sp...

Few studies of tripartite mycoheterotrophic systems have examined ecological specificity across broad geographic ranges or addressed autotrophic host specificity. Pterospora andromedea was selected as an ideal candidate to examine ecological specificity of a mycoheterotrophic system as it is widely distributed, has been shown to have high levels of...

Premise of the study: Pterospora andromedea (Ericaceae ) is a mycoheterotrophic plant endemic to North America with a disjunct distribution. Eastern populations are in decline compared to western populations. Microsatellite loci will allow comparison of genetic diversity in endangered to nonthreatened populations. • Methods and Results: Illumina Mi...

Two species: Russula shingbaensis (R. subg. Heterophyllidia), characterized morphologically by greyish-green to slightly lilac pileus having tuberculately striate-sulcate margin, a stipe with a combination of white and vine colours, multichambered stipe context, indistinctive taste, spores ornamented with isolated warts, pilear elements with chains...

Premise of the study: Rhizopogon kretzerae and R. salebrosus (Rhizopogonaceae) are ectomycorrhizal fungi symbiotic with pines and the mycoheterotrophic plant Pterospora andromedea (Ericaceae). Microsatellite loci will allow population genetic study of fungal hosts to P. andromedea. •Methods and Results: Shotgun pyrosequencing of R. kretzerae DNA re...

The first species of Rhizopogon subgenus Amylopogon identified from eastern North America is described here as Rhizopogon kretzerae Grubisha, Dowie, & Mill. sp. nov. In nature, R. kretzerae has been identified only from DNA sequences of the nuclear ribosomal internal transcribed spacer region (ITS) from mycorrhizal roots of Pinus strobus L. and Pte...

Morphological and ecological descriptions, illustrations, and taxonomic discussions are presented for a subiculate species of Lactifluus, L. subiculatus, and three species of Russula, R. myrmecobroma, R. paxilliformis, and R. gelatinivelata, all newly described from the Pakaraima Mountains of Guyana. Sequence data confirm relationships of taxa coll...

This study was a preliminary analysis of the genetic structure of the ectomycorrhizal species Russula discopus, R. pseudocarmecina and R. ochraceorivulosa with disjunct distributions in continental Africa and Madagascar. Phylogenetic analyses of the nuclear ITS1/5.8S/ITS2 region and the mitochondrial atp6 gene were performed with specimens from bot...

Ectomycorrhizal (ECM) fungi historically were considered poorly represented in Neotropical forests but in the central Guiana Shield substantial areas are dominated by leguminous ECM trees. In the Upper Potaro Basin of Western Guyana, ECM fungi were sampled for 7 years during the rainy seasons of 2000–2008 in three 1-ha plots in primary monodominant...

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 fr...

Mycoheterotrophic plants are nonphotosynthetic and must form a relationship with a mutualistic fungus and an autotrophic host to acquire carbon. In this study, identity of fungal associates of Pterospora andromedea in the south-central Rocky Mountains was determined. Although P. andromedea has been found to associate with at least three Rhizopogon...

Pterospora andromedea, a mycoheterotroph, has been shown to form obligate symbioses with only three species of Rhizopogon in section Amylopogon: R. salebrosus, R. arctostaphyli and an undescribed molecular taxon. Sarcodes sanguinea, another my coheterotroph in Ericaceae, and sister taxon to Pterospora andromedea, has been found to form symbioses wi...

Diversity has various meanings but generally they reflect the variation in species assemblages within a community. Species establish interpopulation relationships that lead to stable community structure, and stable and resilient communities by definition contain a certain level of diversity. Communities with too great or too little diversity predic...

Belowground responses to aboveground disturbance were studied in experimental gaps created in a 95-year-old Pinuscontorta ssp. latifolia (Engelm. ex Wats.) Critchfield stand, southeastern Wyoming. We hypothesized that active fine root densities within the canopy gaps would remain comparable with densities in undisturbed forest and would not decline...

Ectomycorrhiza formation, survivability, and physiognomic characteristics were assessed for conifer seedlings encountered 1 and 2 years postfire in the Huck burn site near Grand Teton National Park. Pinus contorta Dougl. ex Loud. germinated and was abundant throughout the first growing season. Abies lasiocarpa (Hook.) Nutt. germinated during May an...

Spore wall architecture and ontogeny of ornamentation in several genera and species of hypogeous and gasteroid Russulales are similar to those described previously for agaricoid Lactarius lignyotellus. Spore walls are composed of four layers, each differing in thickness and electron density. Layer 2 is electron transparent and corresponds to a dark...

Critical ecological research on belowground ecosystems has often been impeded because of the inability to adequately recognize ectomycorrhizal relationships, especially the abundance, diversity, and distribution of the fungus component, and the specificity of particular fungus–host combinations. Red alder, with its high degree of host specificity a...

This study reports the pure culture isolation of Elaphomyces muricatus Fries for the first time and the subsequent formation of ectomycorrhizae with Pinus sylvestris (L.). Synthesized Elaphomyces muricatus ectomycorrhizae had a tightly appressed mantle of irregular syncnchyma and a well-developed Hartig net. Extramatrical hyphae were thick walled w...

Intensive recreational use of subalpine forests can create localized areas of concentrated disturbance where vegetation is altered, soils compacted, and surface fuels depleted. Many aspects of this disturbance type have been studied, but no research has focused on the effects of recreational use on mycorrhizal fungus sporocarp production. We measur...

We identified relationships between prescribed burn treatments and selected soil and fuel attributes on mycorrhizal fungus fruiting patterns in an old-growth ponderosa pine (Pinus ponderosa) and white fir (Abies concolor) stand in Crater Lake National Park, Oregon, USA. Three prescribed burn treatments (early spring, late spring, and fall burns) pl...

Two new species, viz., Russula koleggiensis and R. netrabaricus has been proposed in the present communication. Their phylogenetic positions within the genus Russula are supported by macroscopic, microscopic characters and rDNA sequences in the ITS gene region.

A phylogenetic analysis of Lactarius sect. Deliciosi was performed based on collections of all known species. Several samples of each species were included, originating from a wide geographic range. The two DNA regions we used (ITS and a part of the gene encoding glyceraldehyde-3-phosphate dehydrogenase) showed an incongruent phylogenetic signal. M...

A phylogenetic analysis of Lactarius sect. Deliciosi was performed based on collections of all known species. Several samples of each species were included, originating from a wide geographic range. The two DNA regions we used (ITS and a part of the gene encoding glyceraldehyde-3-phosphate dehydrogenase) showed an incongruent phylogenetic signal. M...

Cantharellus pleurotoides sp. nov. (Cantharellaceae, Cantharellales, Basidiomycota) is described from the Pakaraima Mountains of Guyana, occurring in rainforests dominated by ectomycorrhizal Dicymbe spp. (Caesalpiniaceae). This fungus is singular among Cantharellus species described worldwide in possessing a pleurotoid basidioma. Macromorphological...

The Russulales is one of 12 major lineages recently elucidated by molecular sequence data in the homobasidiomycetes. The order is morphologically most diverse, containing a remarkable variety of sporophore forms including resupinate, discoid, effused-reflexed, clavarioid, pileate, or gasteroid and hymenophore configurations from smooth, poroid, hyd...

The Russulales is one of 12 major lineages recently elucidated by molecular sequence data in the homobasidiomycetes. The order is morphologically most diverse, containing a remarkable variety of sporophore forms including resupinate, discoid, effused-reflexed, clavarioid, pileate, or gasteroid and hymenophore configurations from smooth, poroid, hyd...

Pseudotulostoma volvata (O. K. Mill. and T. W. Henkel) is a morphologically unusual member of the otherwise hypogeous Elaphomycetaceae due to its epigeous habit and exposed gleba borne on an elevated stalk at maturity. Field observations in Guyana indicated that P. volvata was restricted to rain forests dominated by ectomycorrhizal (EM) Dicymbe cor...

Gymnomyces xerophilus sp. nov., a sequestrate species in the Russulaceae, is characterized and described morphologically as a new species from Quercus-dominated woodlands in California. ITS sequences recovered from healthy, ectomycorrhizal roots of Quercus douglasii and Q. wislizeni matched those of G. xerophilus basidiomata, confirming the ectomyc...

This paper deals with the 13 American species in Lactarius sect. Deliciosi that are supported or revealed in a molecular phylogenetic study of this section on a worldwide scale. Elaborate macro- and microscopical descriptions are given and illustrated for every species. Type specimens for nearly all taxa were examined in this study. None of the tax...

Russula mayawatiana, R. dhakuriana, R. appendiculata and R. puellaris var. atrii are proposed here as new taxa. Phylogenetic positions within the genus Russula are supported by macroscopic and microscopic characters as well as rDNA sequences in the ITS gene region.

Russula brevipes is common ectomycorrhizal (EM) fungus that is associated with several hosts across temperate forest ecosystems. A previous study has demonstrated that substructuring across large geographic distances (1500 km) occurs in the western USA. To examine genetic structure over a more localized scale, basidiocarps of Russula brevipes from...

Russula mukteshwarica, a species closely related to R. violeipes, is proposed here as new to science. Macro- and micromorphological characters of this species are described and illustrated in detail.

Six microsatellite loci were isolated and characterized from genomic libraries enriched for (CA)n (GA)n (ATG)n, and (CAG)n, microsatellite motifs from Russula brevipes, a common ectomycorrhizal fungus that forms mutualisms with several species of trees in North America. The polymerase chain reaction primers were tested on 27 sporocarps of R. brevip...

Macowanites arenicola is proposed and described as a new species. Information is provided on the ecology, morphology, anatomy and comparisons are made with related agaricoid taxa.

Russula billsii is proposed and described as a new species. This species is closely related to R. burlinghamiae and R. ballouii from the southeastern United States and R. viscida and R. ochroleuca from Europe. Information is provided on the ecology, morphology, and anatomy and comparisons are made with related taxa.

Summary • The spatial mapping of genets from sporocarps allows determination of the primary modes of reproduction of ectomycorrhizal fungi. The goals of this research were to determine the relative size, density, and persistence of genets of Russula brevipes , a late successional basidiomycete, in mature stands of lodgepole pine ( Pinus contorta )...

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.

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.

Species in the large mushroom genus Russula are important ecologically as ectomycorrhizal fungi and economically as comestibles. Most infrageneric classification schemes of this genus have originated in Europe, but because of nomenclatural history and an evolving suite of characters these systems remain largely incongruent. Using ribosomal DNA sequ...

Pseudotulostoma volvata gen. sp. nov. is described from the south-central Pakaraima Mountains of Guyana. Pseudotulostoma volvata is associated with ectomycorrhizal Dicymbe corymbosa trees (Caesalpiniaceae) and placed in the Ascomycota, Eurotiales, Elaphomycetaceae. Included are a description of the genus and species, illustrations of the macroscopi...

The Russulales consists of agaricoid, gasteroid and hypogeous gasteroid taxa of basidiomycetes closely related to Russula and Lactarius. Because there have been no molecular phylogenetic studies of the Russulales, attempts at formulating a natural classification for these taxa have met with difficulty. In this study, nuclear large subunit rDNA (n-L...

The Russulales consists of agaricoid, gasteroid and hypogeous gasteroid taxa of basidiomycetes closely related to Russula and Lactarius. Because there have been no molecular phylogenetic studies of the Russulales, attempts at formulating a natural classification for these taxa have met with difficulty. In this study, nuclear large subunit rDNA (n-L...

Three species of pleurotoid, putatively lignicolous basidiomycetes previously described in the genus Lactarius sect Panuoidei were redescribed from fresh material collected in Guyana and Japan. In Guyana, Lactarius panuoides and Lactarius campinensis were restricted to forests dominated by ectomycorrhizal Diqymbe species (Caesalpiniaceae) and basid...

Three species of pleurotoid, putatively lignicolous basidiomycetes previously described in the genus Lactarius sect Panuoideiwere redescribed from fresh material collected in Guyana and Japan. In Guyana, Lactarius panuoides and Lactarius campinensis were restricted to forests dominated by ectomycorrhizal Dicymbe species (Caesalpiniaceae) and basidi...

Two species of hypogeous basidiomycetes in the genus Zelleromyces which had been previously recognized as provisional taxa from the southeastern United States, Z. sculptisporus and Z. versicaulis, are formally described as new. Additional discussion is provided for Z. cinnabarinus, and Z. ravenelii, another species described from the southeastern U...

Ectomycorrhiza formation, survivability, and physiognomic characteristics were assessed for conifer seedlings encountered 1 and 2 years postfire in the Huck burn site near Grand Teton National Park. Pinus contorta Dougl. ex Loud. germinated and was abundant throughout the first growing season. Abies lasiocarpa (Hook.) Nutt. germinated during May an...

This chapter presents a quantitative treatment of the strategies of nutrient uptake by tree root systems building on a biophysical model of the soil–root system. The model is used as a tool for synthesizing existing information on conifer root dynamics and the soil environment. The chapter reviews some implications of crucial root system characteri...

Belowground responses to aboveground disturbance were studied in experimental gaps created in a 95-yr-old stand of Pinus contorta in southeastern Wyoming. One-, 5-, 15-, and 30-tree clusters were felled to create a series of gaps in the root mat, and solution-phase N was monitored over two consecutive snow-melt periods via tension-tube water collec...

Locations of epigeous basidiocarps of five common ectomycorrhizal fungi with substantial spore deposits beneath them and of two hypogeous species were marked in the fall. Subsamples of the litter and mineral soil at 0- to 3- and 3- to 6-cm depths were subsequently taken with a soil corer from locations marked for epigeous basidiocarps, and extracte...

Locations of epigeous basidiocarps of five common ectomycorrhizal fungi with substantial spore deposits beneath them and of two hypogeous species were marked in the fall. Subsamples of the litter and mineral soil at 0- to 3- and 3- to 6-cm depths were subsequently taken with a soil corer from locations marked for epigeous basidiocarps, and extracte...

Spores of the ectomycorrhizal basidiomycetes Rhizopogon rubescens and Suillus tomentosus were induced to germinate and stained with fluorescent stains FDA and DAPI to assess germinability and viability. Basidiospores of several saprotrophic species including Pleurotus ostreatus, Marasmius oreades, Agaricus brunnescens, Coprinus quadrifidus and Cono...

The potential for mycorrhizal formation and Frankia nodulation were studied in soils from six sites in the Pacific Northwest. The sites included young and old alder stands, a 1-year-old conifer clear-cut, a young conifer plantation, and rotation-aged and old-growth conifer stands. A bioassay procedure was used with both red alder and Douglas fir se...

Movement of ectomycorrhizal fungal propagules by small mammals into burned areas of the Huck fire, John D. Rockefeller Memorial Parkway, was monitored for a third field season by live-trapping small mammals in burned and unburned forest sites and examining spores contained in their fecal pellets. As in the first two years, three species of small ma...

One primary objective of this study was to survey small mammal communities in a burn chronosequence. During the summer of 1990, small mammals were live-trapped in five burned sites and in adjacent unburned coniferous forests in and around Grand Teton National Park. In 1991, two burns (Huckleberry Mountain, 1988 fires) and adjacent unburned forests...

In our initial survey of dispersal of spores into areas disturbed by the 1988 Huckleberry burn, in the John D. Rockefeller Memorial Parkway, we focused on small mammal dispersal of hypogeous ectomycorrhizal fungi which had been touted as a primary means of dispersal (Trappe and Maser 1977, Ure and Maser 1982), and the recruitment and physiognomy of...

Ponderosa pine seedlings were inoculated with Hebeloma crustuliniforme either in growth pouches before they were transplanted to root-mycocosms (P seedlings), or at the time of transfer to root-mycocosms (V seedlings). Uninoculated seedlings served as controls (U seedlings). The use of root-mycocosms allowed examination of portions of hyphae separa...

The persistence of mycorrhizal fungi in undisturbed coniferous forest ecosystems is assumed by the renewed appearance of their sporocarps each year. Sporocarps, however, are not produced in areas severely disturbed by fire or clearcutting; yet spores and other propagules of some species of hypogeous fungi are present in the soil in the absence of s...

A culture system is described to grow mycorrhizal plants which allows experimental measurements to be made on mycorrhizae, and a portion of intact ectomycorrhizal fungi while in symbiosis, but growing apart from the rooting medium and host roots. A portion of the extramatrical hyphae is kept apart from the rooting medium by a restrictive passageway...

Late basidiospore development was examined in seven heterotropic and orthotropic species of Russulales. In Lactarius, Russula, Macowanites, Elasmomyces, Martellia, and Zelleromyces, a transverse electron-transparent region developed in the sterigmal apex that separated sterigmal cytoplasm from basidiospore cytoplasm. A plug-forming body descended i...

Basidiospore formation in Lactarius lignyotellus is a complex phenomenon involving cytoplasmic and wall layer synthesis and interaction. Four stages in early basidiospore development prior to nuclear migration into the spore cytoplasm were delineated, as evidenced by changes in gross morphology, wall tegumentation, and cytoplasmic differentiation....

Basidiospore formation in Lactarias lignyotellus is a complex phenomenon involving cytoplasmic and wall layer synthesis and interaction. Four stages in early basidiospore development prior to nuclear migration into the spore cytoplasm were delineated, as evidenced by changes in gross morphology, wall tegumentation, and cytoplasmic differentiation....

The research underway has two primary objectives. The first objective is to collect and identify the species of hypogeous fungi associated with ectomycorrhizal vascular plant hosts occurring in Grand Teton National Park and the John D. Rockefeller Memorial Parkway (GTNP) over a 3 year period. Upon completion of the inventory, distribution, host spe...