"Just as flowering plants -- trees, shrubs and herbs -- grow in more or less well defined communities in fields, hedgerows, marshes, sand-dunes, woodlands, so do mushrooms and toadstools. If we consider microfungi, this is self-evident, for many of them are specialized parasites, strictly confined to definite host plants; and their distribution has its limits set by that of the possible victims; entomogenous fungi are dependent upon the presence of the host insect for their occurrence; and saprophytic species, as they are frequently particular in their diets may be assumed to be restricted in their range in relation to the substrata capable of providing them with nutriment."--from Ramsbottom, J. 1954. Mushrooms and Toadstools. Collins, London.

I. Objectives: The following experiments/demonstrations are the consequence of my having selected what seemed to me to be three "Great Ideas" ln fungal ecology. They are meant to illustrate, through an inductive process, major concepts about fungal communities and the importance of fungi in ecosystems.

• Petri plates, erlenmeyer flasks, large-bore (serological large tip) 1 and 2 ml pipettes
• Soil, preferably from a native community (often fewer dominant species, though more total species than in manipulated communities)
• Soil extract medium or Brown or Gochenaur medium (See Refs.)
• Potato-dextrose agar
• Test tubes
• Microscalpel (sharpened sewing needle fused in 5 mm glass tubing)
• Alcohol and burner, for sterilizing tools
• Zephiran solution or other surface disinfectant
• Autoclave, Mettler balance.

1. As in the litter decomposition experiment , the students should be encouraged to come up with Observation, Hypothesis, and Experimental Method.
2. The dilution plate technique account given to beginning mycology students at Wyoming is available as a separate handout. We've found that 20-25 isolates from each of 4-10 collection sites in the selected study area (a relatively homogeneous forest or grassland) provide sufficient quantitative data for comparisons. If the class agrees to concentrated effort in a single area, 10 collection sites is desirable. Our students usually elect to work in pairs, with one team assigned to each site sample. Sorting to "taxonomic entity" is by gross appearance of same-aged tube cultures. If it's appropriate for the course, some students no doubt will undertake species identifications; identification is not essential to validation of the concept however.
3. The fungal community analyses that can be made include: species diversity determinations (i.e. species obtained among a standard number of isolates); structure analysis (e.g. what percent of the species occurred at half or more of the sites); 2w/a+b compositional comparisons among communities, using entire assemblages or high-frequency forms only; and analysis by construction of Peyronel diagrams (See Refs 1 and 2). Numerous studies in the U.S., Britain, Poland, and elsewhere have confirmed that in relatively undisturbed soils, only a few microfungal species are high-frequency or "constant" species (See Refs 3-7) and that assemblage is as distinctive, for any given community or community type, as are the assemblages of principal producer and consumer organisms.

IV. Conclusion: Saprophytic microfungi associate in discernible communities (synusia) which appear to be habitat specific. Community composition and structure can be related to cover vegetation. The specific controlling factors, however, may be chemical/physical features of the soil environment and interspecific competition. On the basis of the data at hand, it seems logical to postulate that the species in a given habitat are more efficient in that habitat than are others.

Badura, L. 1965. Investigations on the soil mycoflora of a beech community in the Botanical Garden of the Turin University (Italy). Fragmenta Floristics et Geobotanical 11: 197-208.

Badurowa, M. and L. Badura. 1967. Further investigations on the relationship between soil fungi and the macroflora. Acta Soc. Bot. Pol. 36: 515-529.

Brown, J.C. 1958. Soil fungi of some British sand dunes in relation to soil type and succession. J. Ecology 46: 641-664.

Christensen, M. 1969. Soil microfungi of dry to mesic conifer-hardwood forests in northern Wisconsin. Ecology 50: 9-27.

Gochenaur, S.E. and W.F. Whittingham. 1967. Mycoecology of willow and cottonwood lowland communities in southern Wisconsin. I. Soil microfungi in the willow-cottonwood forests. Mycopathol. Mycol. Appl. 33: 125-139.

Sewell, G.W.F. 1959. The ecology of fungi in Calluna-heathland soils. New Phytol 58: 5-15.

Thornton, R.H. 1956. Fungi occurring in mixed oakwood and heath soil profiles. Trans. Brit. Mycol. Soc. 39: 485-494.