Part 87

Text-figures and line-drawings of the greater number of the fungi mentioned in the text have been included in the book. It is impossible to supply colour pictures of a high quality in a book such as this without raising the price of the publication astronomically. The plates in six easily obtainable popular books have been used to represent whenever possible the fungus described in the text, as accurate colour illustrations are very useful in identification. The titles of these books have been abbreviated for clarity.

Abbreviations for illustrations used throughout the text

F--Findlay, W. P. K. (1967), Wayside and Woodland Fungi, London.

Hvass--Hvass, E. & H. (1961), Mushrooms and Toadstools in Colour, London.

LH--Lange, M. & Hora, F. B. (1963), Collins Guide to Mushrooms and Toadstools, London.

NB--Nicholson, B. E. & Brightman, F. H. (1966), Oxford Book of Flowerless Plants, Oxford.

WD--Wakefield, E. & Dennis, R. W. G. (1950), Common British Fungi, London.

Z--Zeitlmayr, L. (1968), Wild Mushrooms, London.

(iii) Fairy rings

Object: To assess the annual radial growth of fairy-rings and to correlate this with any obvious environmental change.

Materials: Graph and tracing papers, tape-measures, note-book, pencil and rule, small pieces of cane about four inches long and coloured dye (e.g. Eosin solution, Janus Green).

Method: Select a fairy-ring on the school cricket pitch or hockey pitch, school lawn, local golf course or park at a time when the fruit-bodies are first visible. Carefully mark the centre of the ring by driving into the soil a piece of cane until the top is only just visible. Plot this point on graph paper and relate it to any prominent feature nearby, e.g. post, tree or hedge.

Carry out weekly observations throughout the fruiting season plotting the individual fruit-bodies on tracing paper, which is trimmed so as to make a replica of the original graph-sheet. A small dab of coloured dye placed on a fruit-body will assist one in recognising fruit-bodies from previous observations. During the fruiting season observe and plot the zones of differently coloured vegetation--devise some method of describing (and measuring) these colours perhaps by comparison with a colour-chart, printed or hand prepared. Continue observations on the ring at monthly or fortnightly intervals after the disappearance of the fruit-bodies, and record subsequent changes in the vegetation for twelve months.

This project can be continued for several years and for different species of fungus. Weather conditions may be noted simultaneously with the growth observations, or obtained from a reliable source of similar information close by. In this way not only is the increase in ring size measured but the results can be considered in the light of climatic data; fungal growth appears to be dependent on favourable weather conditions.

Further experiments:

(i) Compare the effect that different species of agaric have on the same type of vegetation.

(ii) Observe selected fairy-rings for several seasons then either apply fertilisers, particularly calcium-based fertilisers to the ring-area, or mow the vegetation. Note increase in fruit-body production, if any, changes in period of fructification or increase in rate of ring development.

(iii) Prepare transects across the fairy-ring and observe the species of flowering plants and mosses present, the differences between species in the two stimulated zones, and the colonisation of the dead zone by annuals and later perennial grasses and herbs.

(iv) To the soil from each zone apply simple soil-dilution plate-methods for the culture and isolation of soil fungi and bacteria. Compare the results with those obtained by similar methods from soil without the fairy-ring.

(iv) Development of the agaric fruit-body

In the soil or substrate the hyphae of agarics frequently grow in close contact with each other, indeed the intertwining of such hyphae to form small knots is common in many fungi. In these intertwining hyphae, those close together divide and branch, later branching again to form a heap of tissue. The fruit-body develops from, or within, this knot and at its earliest stage is usually covered by loosely branched and irregularly arranged hyphae. To the unaided eye the primordium, for this is what such a structure or early beginning is called, appears to be enveloped in a mass of pale hyphal strands, often giving the fruit-body a woolly appearance when seated on the soil, wood, herbaceous debris, etc. If more than one primordium develops in close proximity, usually all but one abort early in development, or they remain checked in formation at this stage until those close by have matured. Some species which grow on wood are caespitose, that is clustered together, and in these cases all or many more of the primordia develop fully and simultaneously.

Often it is possible to search and find these primordia in the fields and woods, and if they are examined under the low-power of a microscope it is possible to study how the fruit-body subsequently develops from its small beginnings and the part played by the ring and volva in the development determined. Thus the origin of the veil can be located, its development followed as well as its disintegration. When the fungus is grown in pure culture on sterile dung, or soil, or wood, or simply on artificial media prepared in the laboratory the full sequence of events can be more easily followed. This is how the professional mycologist conducts his observations. By very careful studies it has been found in recent years that the development of the fruit-body, the origin of the gills, etc. can assist in the classification of the higher fungi. Thus some species have no protective tissue around the developing gills (gymnocarpic) whilst others have one or even two, simple or complex, tissues around the developing gills or pores (hemiangiocarpic). It is these tissues which give rise to the ring, volva, cortina, etc. This most exciting part of the study of the higher fungi is illustrated in the accompanying figures (Figs. 12 & 13) along with the various types of gill-attachment mentioned in the text (Fig. 11 A-H). If the agaric has two tissues surrounding it as the cap expands and matures, first the outer tissue or skin breaks leaving pieces on the stem and/or cap and then the second skin breaks as the cap expands still further. The last skin leaves remnants on the stem and sometimes bits and pieces at the cap margin. Only now can the agaric shed its spores from the fully exposed gills.

Fig. 12

Fig. 13

Fig. 14]

(v) References

A. Reference Texts

Some references have already been given on p. 264. Findlay, Hvass & Hvass, Lange & Hora, Nicholson & Brightman, Wakefield and Dennis and Zeitlmayr.