BIOL/CSES 4684

PISOLITHUS

SOIL MICROBIOLOGY

This webpage was created by Jeff Muldoon

1. IDENTIFYING CHARACTERISTICS

Considered one of the ugliest of the fungi.
Sporocarp is oval to club shaped.
Sporocarp divided into compartments called peridioles.
Brownish yellow spores produced.
Yellow to gold to mustard colored hyphae.
Easily propagated in the lab, on a variety of media.
Reported in 33 countries, and 38 states in the US.
Optimum growth 28-30 degrees celsius.
Thermal death point 45 degrees celsius.
Forms beneficial ectomycorrhizal relationships with trees.
Host range of over 75 species of trees.
Not edible.

The picture to the left shows a young Pisolithus sporocarp.

2. TAXONOMIC DESCRIPTION
Pisolithus is a member of the phylum basidiomycotae, in the gasteromycete class. The order is sclerodermatacales, while the family is sclerodermataceae. The genus of Pisolithus has only one member, it is however known by two species names, Pisolithus tinctorius, and Pisolithus arrhizus. Pisolithus means Pea stone (this is in reference to the peridioles), tinctorius comes from the use of this fungus in dying processes, while arrhizus, the latest, means without a root.

The gasteromycetes are a class of fungi which are unable to forcibly discharge their spores. The spores remain within the fruiting body, which is composed of numerous pea sized compartment called peridioles, where they are protected by the sterile outer layers known as the peridium. The peridioles nearest the top develop and enlarge until they break open and give rise to the colored powdery gleba. Younger, less developed peridioles are found in consecutive layers below the mature layers. Once the peridioles are opened the spores are disseminated in a number of ways, the most common being, wind, rain, insects and mammals. Since forcible discharge is not utilized this is known as a statismorphic basidium. Also within this class are the Lycoperdales (puffballs, earth stars, etc.), Tulostomatales (stalked puffballs), Phallales (stinkhorns), and the Nidulariales (birds nests).

The above picture shows a mature Pisolithus tinctorius sporocarp

3. ISOLATION AND ECOLOGY
Pisolithus is most commonly isolated from young, undamaged, sporocarp tissue, but can be isolated from other portions of the fungus as well. Selective media are available, and laboratory cultures are relatively easily grown. Pisolithus is presently used as a commercial inoculum for seedling roots, and has proven capable of undergoing extended storage periods.

Pisolithus is widely distributed, and is often found in adverse environments. Sites are commonly characterized by high summer soil temperatures, extreme acidity, droughtiness, low fertility, and high levels of toxic metals. This combined with Pisolithus's ability to form extensive mycorrhizal relations with numerous tree species makes it quite popular in reclamation efforts. Pisolithus has proven quite capable of surviving on acid coal spoils, as well as kaolin spoils and severely eroded sites in the southeastern United States. It has also been shown to greatly improve the ability of seedlings to grow, and prosper on such adverse sites. Concentrations of essential nutrients are much higher in trees that form an ectomycorrhizal association with Pisolithus.

4. ADDITIONAL SOURCES OF INFORMATION
Miller, Orson K. 1988 Gasteromycetes, Morphological and Developmental Features. Mad River Press Eureka, California.

Weber, Nancy S. 1988 A Field Guide to Southern Mushrooms. University of Michigan.

Schenck, N.C. 1982 Methods and Principles of Mycorrhizal Research. The American Phytopathological Society St. Paul, Minnesota.

Marx, Donald H. 1979 Pisolithus Tinctorius, Ectomycorrhizeae Improve Survival and Growth of Pine Seedlings on Acid Coal Spoils in Kentucky and Virginia. The Reclamation Review vol. 2 pp. 23-31 U.S.A.

5. LINKS TO OTHER SITES ON PISOLITHUS
ECTOMYCORRHIZEAE This site contains concise descriptions of the ectomycorrhizeae.