The Mushroom Season

When the rains come in October they signal the beginning of the mushroom season. The season when the fungi, hidden beneath the ground, produce their flowers. For mycophiles, people who love mushrooms, this is the best season of the year. There is something about mushrooms, and the way they seem to arise spontaneously, that elicits a sense of wonder. Many cities have mushroom clubs that put on an annual mushroom show. Year after year people come out to these shows by the hundreds. Why is this so? What is it about mushrooms? Birds, trees, insects, geology, none of them can generate this level of sustained interest. As a channel into the mysteries of nature, mushrooms outdo them all. 

Why do mushrooms come out in October in greater profusion than at any other time of the year? To understand that we need to know what mushrooms are, and what they are doing. Mushrooms present a transient glimpse into an invisible, mostly microscopic world hidden beneath the soil. They do for fungi what flowers do for plants, reproduce the organisms producing them. Whereas flowers are smaller than the plants producing them, mushrooms are larger than the fungi that give rise to them. Flowers result in large seeds that are easily seen, but mushrooms produce spores, that function like seeds, but which can only be seen with a microscope.

Some mushrooms fruit in the spring, but most of them choose the autumn to do so. There is ample moisture for the mycelium - the underground, mold-like part of the organism, which gathers nutrients from organic matter or tree roots. There is also ample moisture for the germinating spores. Those spores produce fungal threads which over-winter, and then are really ready to grow once the spring rains arrive. Different mushroom mycelia have different life styles.  There are basically two of those life styles. They either tear down or build up. Some species are recyclers. They rot down organic matter such as wood, old leaves, or manure and send their byproducts back into the soil to be used by succeeding generations of plants or trees. The cultivated kinds of mushrooms belong to this group. The button mushroom lives on manure. Oyster mushrooms, enokis, and shiitakes are grown on logs or wood chips.

The other life style is the mycorrhizal one. Mycorrhiza means fungus root. The mushroom mycelium is attached to the roots of a tree, and both the mushrooms and the tree are dependent on each other for their survival. The microscopic fungal threads grow outward into the surrounding soil, gathering moisture and minerals such as phosphorus, and delivering them to the tree roots. In return the fungus takes some of the sugars made by the tree’s leaves to build its own tissues. The thin threads of the fungus travel far beyond the tree roots themselves, and although they are very small, in total, they have more surface area than the roots themselves, and therefore are very efficient at scavenging water and nutrients. Many trees could not survive the summer drought without their mushroom helpers. Many of the mushrooms growing on the forest floor are produced by mycorrhizal fungi, including some of the most sought after ones, such as chanterelles (Cantharellus formosus), pine mushrooms (Tricholoma magnivelare), and king boletes (Boletus edulis).  

Rough-stem Bolete (Leccinum scabrum) is a mycorrhizal partner of birches.

Photo by Terry Taylor

How many different mushrooms are there in British Columbia? Nobody knows for sure, but the number of species is in the thousands, not hundreds. The most detailed study ever done in  the province is at Observatory Hill near Victoria. As of 2009 it had been going on for five years. Although this is just a small hill, less than 100 hectares in area, 800 different kinds of mushrooms have been identified, and more are likely to be discovered. This gives an inkling of the complexity and diversity of the mushroom world. There are many more mushrooms out there than we imagined. If you cannot identify your shroom after carefully looking in a mushroom book, do not feel discouraged. Even the experts cannot identify a large number of them, because there are many that have yet to be named. Of those which are named, a large percentage require microscopic study before they can be distinguished from their close relatives. 

There are, however, a fair number which can be easily identified. Chanterelles, shaggy manes, oyster mushrooms, king boletes, and pine mushrooms are among this group. These are some of the prizes to be collected by the mushroom hunter when the rains come. By September fungal enthusiasts can hardly wait for the summer to be over. This does not mean, however, that you should buy a book, rush out into the woods, and greedily devour what you think you can eat. There are a number of poisonous look-alikes. Every year poison control centres have to deal with those who have made a mistake. Most of the time these people come away with merely a few unpleasant experiences, but that is not always the case. The old saying in mushroom clubs that “there are lots of old mushroom collectors, and lots of bold mushroom collectors, but no old bold mushroom collectors” is something to keep in mind. Start your new adventure by going out with an experienced mushroomer, or on a mushroom club field excursion. Identifying your finds by a picture in a book isn’t good enough.