Rhizopogon

Historical classification The genus Rhizopogon occurs throughout the natural and introduced ranges of family Pinaceae trees. Though this range covers much of the northern temperate zones, the diversity of Rhizopogon species is well characterized only in North America and Europe. , there were over 220 recognized species of Rhizopogon. The morphology of Rhizopogon species is highly cryptic and characters vary greatly throughout sporocarp maturity. This has led to the description of multiple species from various developmental stages of a single fungus. The genus Rhizopogon was first described from Europe by Elias Magnus Fries in 1817. The North American monograph was produced by Alexander H. Smith in 1966 with second author credits given posthumously to Sanford Myron Zeller due to his contributions to the study of the genus. A European monograph of Rhizopogon has also been published. In the recent past, molecular phylogenetic methods have allowed the revision of the taxonomic concepts of the genus Rhizopogon. Modern classification Modern taxonomic concepts of the genus Rhizopogon recognize five subgenera of Rhizopogon. These are subgenus Rhizopogon, subgenus Versicolores, subgenus Villosuli, subgenus Amylopogon, and subgenus Roseoli. ==Ecology==

Mammalian diet and spore dispersal Rhizopogon species have been established as a common component in the diet of many small mammals as well as deer in Western North America. The viability of Rhizopogon spores is maintained and may even be increased after mammalian gut passage, Rhizopogon spores are long lived in soil and the spores of some species can persist for at least four years with an increase in viability over time. Rhizopogon seems to be especially common upon the roots of establishing tree seedlings following disturbance such as fire or logging. Rhizopogon are also abundant colonizers of pot cultivated and field cultivated The enzymes exuded from some species within the subgenus Amylopogon is essential in activating seed germination in some species of Monotropoideae, such as Pterspora andromedeae. This makes Rhizopogon an obligatory host to species like P. andromedeae. The exoenzymatic activity also confers higher competitive advantages to host species, This exoenzymatic activity is nitrogen limited. Species • Rhizopogon albidus • Rhizopogon ater • Rhizopogon atroviolaceus • Rhizopogon brunneniger • Rhizopogon ellenae • Rhizopogon evadens • Rhizopogon fulvigleba • Rhizopogon fuscorubens • Rhizopogon hawkerae • Rhizopogon himalayensis • Rhizopogon luteolus • Rhizopogon nigrescens • Rhizopogon occidentalis • Rhizopogon ochraceorubens • Rhizopogon parksii • Rhizopogon parvisporus • Rhizopogon pedicellus • Rhizopogon roseolus • Rhizopogon salebrosus • Rhizopogon subareolatus • Rhizopogon subaustralis • Rhizopogon subcaerulescens • Rhizopogon subpurpurascens • Rhizopogon subsalmonius • Rhizopogon succosus • Rhizopogon togasawariana • Rhizopogon truncatus • Rhizopogon vesiculosus • Rhizopogon villosulus • Rhizopogon vinicolor • Rhizopogon vulgaris ==Ethnomycology==

Forestry The first intentional use of Rhizopogon species in forestry occurred in the early part of the 20th century when Rhizopogon luteolus was deliberately introduced into Pinus radiata plantations in Western Australia after it was observed to improve tree growth. Since that time, Rhizopogon species have been widely studied as a component of managed forests. Rhizopogon species have been noted as common members of the ectomycorrhizal community colonizing tree roots of pine and Douglas-fir timber plantations. Naturally occurring Rhizopogon roseolus (=rubescens) spores have been shown to out-compete the spores of other ectomycorrhizal fungi in pine plantations even when competing spores were directly inoculated onto seedlings. The survival rate and performance of pine and Douglas-fir plantation seedlings are increased after inoculation with Rhizopogon species. Gastronomy Though this genera is considered edible, most members are not held in high culinary esteem. A notable exception is R. roseolus, which is considered a delicacy in Japan, where it is traditionally known as shōro. Techniques for the commercial cultivation of this fungus in pine plantations have been developed and applied with successful results in Japan and New Zealand. ==References==