Rhizopogon is a hypogeous fungal genus that forms ectomycorrhizae
with genera of the Pinaceae. The greatest number and species of
Rhizopogon are found in coniferous forests of the Pacific Northwestern
United States, where members of the Pinaceae are also concentrated.
Rhizopogon spp. are host-specific primarily with Pinus spp. and
Pseudotsuga spp. and thus are an important component of these forest
ecosystems. Rhizopogon includes over 100 species; however, the
systematics of Rhizopogon have not been well understood. Currently the
genus is placed in the Boletales, an order of ectomycorrhizal fungi that are
primarily epigeous and have a tubular hymenium. Suillus is a stipitate
genus closely related to Rhizopogon that is also in the Boletales and host
specific with Pinaceae. I examined the relationship of Rhizopogon to
Suillus and other genera in the Boletales. Infrageneric relationships in
Rhizopogon were also investigated to test current taxonomic hypotheses
and species concepts. Through phylogenetic analyses of large subunit and
internal transcribed spacer nuclear ribosomal DNA sequences, I found that
Rhizopogon and Suillus formed distinct monophyletic groups.
Rhizopogon was composed of four distinct groups; sections Amylopogon
and Villosuli were strongly supported monophyletic groups. Section
Rhizopogon was not monophyletic, and formed two distinct clades. Section
Fulviglebae formed a strongly supported group within section Villosuli.
Taxonomic revisions were proposed. Suillus, Truncocolumella, and the
Gomphidiaceae were transferred to the Rhizopogonaceae. In Rhizopogon,
sections Amylopogon, Rhizopogon, and Villosuli were elevated to
subgenera. Subgenus Roseoli was erected to accommodate the second
section Rhizopogon Glade. In section Fulviglebae, Stirps Vinicolor,
Rhizopogon ochraceisporus, R. subclavitisporus, and R. clavitisporus were
transferred to subgenus Villosuli while the remaining species in section
Fulviglebae were transferred to subgenus Rhizopogon. / Graduation date: 1999
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/36754 |
| Date | 22 June 1998 |
| Creators | Grubisha, Lisa C. |
| Contributors | Spatafora, Joseph W. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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