Draft of Rhizopogon salebrosus A.H. Sm. for 2008/2009 EOL University Species Pages Initiative by Tom Bruns

Title: Draft For 2008/2009 Eol University Species Pages Initiative By Tom Bruns (Public)
Name: Rhizopogon salebrosus A.H. Sm.
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 Draft For 2008/2009 Eol University Species Pages Initiative By Tom Bruns (Public) [Edit]

Description status: Unreviewed

General Description:

Rhizopogon salebrosus produces underground truffle-like fruiting bodies. Young fruiting bodies are pure white and have a slightly fluffy look to the peridium, which will turn blue then black (or straight to black) in 3% KOH. In age the peridium becomes brownish and matted in appearance, but will retain the same KOH reaction. In some specimens the peridium stains bluish where handled. The gleba (internal spore-containing tissues) are cocco-chocolate brown at maturity. Spores are oblong, mostly 7-9 X 2.8-3.5 micrometers. Its mycorrhizae on pine are pure white, densely clustered, and highly rhizomorphic with rhizomorphs often staining dark blue with handling. This general description fits most species in the section Amylopogon.

Diagnostic Description:

The diagnostic features such as gleba color, staining reactions, chemical reactions, and minute differences in spore sizes used to separate this species from it close relatives in the original description by Smith and Zeller (1966)^1^ do not appear to be valid when multiple collections are compared and nucleotide sequences are employed (see look alikes below).


Rhizopogon salebrosus was originally described from Idaho, but it appears to be common throughout pine forests in montane and coastal regions of Western North America. It has been found as far north as British Colombia and as far south as the Southern Sierra Nevada in California. Along the California coast it is common from Pt. Reyes National Sea Shore North, but from Monterey South it appears to be replaced by closely related species such as R. brunsii 2, 3.


Rhizopogon salebrosus is an ectomycorrhizal associate of the Pinaceae. Its most common hosts appear to be members of the genus Pinus, although it may also associate with Douglas-fir and true fir (Abies). It occurs in both young, post-disturbance, pine forests and mature pine forests. In both settings rodents, deer, and other mammals eat its underground truffle-like fruiting bodies, and its spores are dispersed in their dung. Spores may lay quiescently in the soil for years and germinate in response to pine roots.

It is also one of the two host species for pine drops, Pterospora andromedea, an epiparasitic plant that lacks chlorophyll and obtains all its fixed carbon from surrounding trees through its connection with either R. salebrosus or R. arctostaphyli^4^.

Look Alikes:

Rhizopogon salebrosus is in section Amylopogon of the genus Rhizopogon. Species in this section look remarkably similar to each other and are developmentally variable, and phenotypically plastic. As a result the general description of the species could be applied equally well to many other species in the section. Our current concept of the R. salebrosus is based on nucleotide sequence analysis of the ITS region. The holotype collections (i.e., those used to define the species in the original description) have been sequenced for most species in section Amylopogon^4^. From these data we know that R. salebrosus(holotype AF351874) is distinct from R. ellenae(holotype AH011350), and R. arctostaphyli(holotype AF377167) the two most common species that it might be confused with, but it can not be differentiated from R. fallax(paratypes AF377143 ,AF377144), R. semireticulatus(holotype AF377119), R. subgelatinosus(paratypes AF377146 ,AF377147 ) and R. subbadius(holotype AF377152 ) based on sequence data from this single locus. In the older literature the name R. salebrosus was rarely applied, and most collections of it were identified as R. subcaerulescens(holotype AF377120 ), a name which is now considered to be a synonym with R. ellenae.


Along with other Rhizopogon species it is occasionally used for inoculation of pine seedlings in forestry^5^, it has been used for ecological research on mycorrhizae, and the complete genome of R. salebrosus is now scheduled to be determined by the Joint Genome Institute.


1 Smith, A.H. and S.M. Zeller. 1966. A preliminary account of the North American Species of Rhizopogon. Mem. NY Bot Gard. , 14: p. 1-177.
2 KjĂžller, R. and T.D. Bruns. 2003. Rhizopogon spore bank communities: within and among Californian pine forests. Mycologia, 95: p. 603-613.
3 Grubisha, L.C., J.M. Trappe, A.R. Beyerle, and D. Wheeler. 2005. NATS truffle and truffle-like fungi 12: Rhizopogon ater sp nov and R. brunsii sp nov (Rhizopogonaceae, Basidiomycota). Mycotaxon, 93: p. 345-353.
4 Bidartondo, M.I. and T.D. Bruns. 2001. Extreme specificity in epiparasitic Monotropoideae (Ericaceae): Widespread phylogenetic and geographic structure. Molecular Ecology, 10: p. 2285-2295.
5 Castellano, M.A. and R. Molina. 1989. The biological component: nursery pests and mycorrhizae., in The container tree nursery manual., T.D. Landis, et al., Editors, USDA Forest Service: Washington, D.C. p. 101-167.

Description author: Tom Bruns (Request Authorship Credit)

Created: 2008-10-27 19:03:29 EDT (-0400) by Tom Bruns (pogon)
Last modified: 2013-05-08 11:37:19 EDT (-0400) by Tom Bruns (pogon)
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