Autumn - the season of renewal

For some people autumn has for too long been associated with a sensation of melancholy, but I like to think of it in terms of harvest followed by the start of a great natural renewal process.

Having largely completed the annual project - the successful production of viable seeds to guarantee the species survives overwinter - plants can now prepare to shed any material no longer needed. All this accumulated material starts to decay and be returned to the earth as humus as the earth's recycling processes swing into action. The resulting sweet, musty smell of autumn is especially noticeable while walking in the warm, humid environment of our local woodlands.

Now is the time when fungi come into prominence, although most of the fungus is hidden below the surface of the soil. What we notice, are just the large fruiting bodies that will shed millions of microscopic spores. Usually referred to as mushrooms and toadstools, these come in all colours and sizes, and some grow into quite spectacular structures.

Ironically, the nursery rhyme image of a toadstool with a white-spotted, red cap on a tall, white stem is the fly agaric, a poisonous species! Fly agaric releases its spores from papery gills found on the underside of this cap and many other species show the same structure, including edible field mushrooms, their commercially produced cultivars, and the large, stately parasols which often can be found on Roborough Down. Those found on dead tree trunks, such as oyster mushrooms have stems growing horizontally before curving up to carry a fan-shaped cap. Although many species of fungi are edible, always remember never to eat them unless you are absolutely sure of their identity - if possible, have it confirmed by someone who is knowledgeable about fungi, since many species are highly toxic and some even deadly!

As an alternative to gills, many species have a spongy underside with the spores being released from the tubular pores including the aptly named 'penny bun' or ceps, as the Boletus edulis is often known, as well as the spectacular, bright yellow puffs of 'chicken in the woods'. Some tree-dwelling species, the 'bracket fungi’, have developed decidedly woody caps that are strong enough to survive and grow for many seasons, producing large shelf-like structures with the annual growth rings clearly visible. The final variation that I will mention are the puffballs, spherical in shape with a tough skin which, as they mature, will eventually split open to release a black cloud of spores. Most are small but the 'giant' puffball may reach the size of a football, and is edible while young and the flesh is still creamy-white.

Of course, what we see above ground or growing out of a tree trunk is only a small fraction of the total body of the whole fungus. The part that we don't normally see is the network of mycorhizal filaments that spread throughout the surface layer of the soil and under the bark of decaying timber. These filaments are thin and delicate, like the fluffy white mould that may be seen on a piece of fruit or vegetable left too long in the bottom of the vegetable rack; the extent and importance of these networks has only been discovered relatively recently. Fungi form a separate biological kingdom equal in status to that of plants and animals. They feed using filaments that penetrate and digest complex organic material and this network maintains the health and life of the plants living in the same soil. It is even thought that plants would not have made the successful move from water to the land if fungal networks had not provided vital minerals essential for plant growth.

Pete Mayston