Wake up and smell the mushrooms

Flowers, of course, have aromas. Animals have scents, though we usually don't get close enough to wild ones to notice. But mushrooms? When was the last time you went on a mushroom-sniffing walk? This winter, when the wet woods fill with fungi, give it a try.

Sure, some mushrooms lack conspicuous smells, and some smell `mushroomy'. That really means they smell vaguely similar to the familiar grocery-store mushroom Agaricus bisporus. (I give Latin names because most mushrooms lack widely accepted common names.) But the ones with distinctive aromas have a range of smells that puts the relative monotony of flower odors to shame.

Perhaps my favorites are the anise- and almond-scented ones. (Almond and anise often turn out to be surprising difficult to distinguish.) Take Clitocybe fragrans - the name gives it away - a delicate white mushroom with gills that may run a bit down the stalk - and a delicate anise scent. It is said to keep the aroma when cooked, but I have never found enough to be worth cooking.

In contrast Hygrophorus bakerensis, which when not too chilly has a powerful almondy aroma, is said to be bland-tasting when cooked. This slimy-topped medium-sized brown woodland mushroom may be the easiest of the anise-almond ones for beginners to find.

Then there is a whole swarm of species in the genus Agaricus - yes, the same genus as the grocery store ones - with anisy/almondy tinges - and the anise-almond-scented Agaricus species are all edible. (All Agarici start out with white or pink gills that gradually darken to a deep chocolaty brown. The young ones have a tissue layer called a veil that covers the gills when young. As the cap grows, the veil ruptures, usually leaving a ring of tissue around the stem.) One specimen of the tall giant Agaricus augustus (see photo) is enough for a fine anisy feast, but dime-sized Agaricus diminutivus is so small and inconspicuous that you might spend a lifetime looking for a decent serving. As with many forms of wildlife, you'll never see diminutivus unless you look for it, but I find it regularly in wet mushroomy Mendocino woods. Pay attention to all the tiny woodland mushrooms, and look for a pale one that is stockier than others of its size and growing alone rather than in swarms. Sniff intently. As with most scented mushrooms, the aroma is strongest from the gills. Even if you don't find diminutivus, you'll probably find something interesting. In grasslands you might find anise-scented and yellow-stained Agaricus arvensis (or quite a number of other anise-scented species).

You can easily find other Agaricus species growing on lawns and curb strips in the city and suburbs, but most of these (even those with yellow stains) will have a very different odor - that of phenol (in the old days known as carbolic acid), most familiar as the odor of Band-Aids^®. Some smell stronger than others, and some people have difficulty picking up this scent, but it is a useful warning - because the phenolic Agarici can give many stomachs a bad upset.

A very different and popular aroma comes from Camarophyllus russocoriaceus. Russocoriaceus means "Russian leather", and the mushroom indeed smells delightfully like cedar chips, sometimes intensely so. This slender off-white mushroom starts off with a tiny cap just a fraction of an inch across which expands to an inch or two, and when it appears you may find it in scattered groups all around the forest.

Perhaps the most controversial aroma is that of Russula fragrantissima. Its gooey but boringly tan caps, several inches across when fully open, have radial striations on the edges. When you sniff, out comes the scent of benzaldehyde, best known as the odor of maraschino cherries. But there must be something more to the scent because most people seem to find it unpleasant, if not downright foul. I, however, am in the minority who find it a delicious smell and wish that this mushroom were edible.

Why do all these mushrooms, from quite unrelated genera, have scents? No one knows. There are just a couple sorts of mushrooms where scientists have a convincing explanation for the scent. Underground mushrooms, from many, many different groups of fungi, tend to acquire strong scents, often more or less musky, when mature. This seems to be an adaptation to make sure that they are found and eaten by animals. The spores then pass through the digestive tract and are deposited in a ball of fertilizer. In the case of the culinary European truffle, the odorant is chemically the same as pig sex pheromones. Some of these scents can be quite pungent, but they clearly attract many gourmets of our species as well.

Stinkhorns, the order Phallales, are a group that put out strong odors that definitely do not attract humans - but they do attract flies, which land on the mushrooms' slimy surface. Spores stick to the flies' feet and are thus transported to new potentially fruitful locations. In my experience stinkhorns are not frequent, but I have repeatedly found Clathrus ruber growing under shrubbery in the Golden Gate Park Museum Concourse. Since these mushrooms grow as a network of bright reddish orange tentacles (like a cage made out of rusty chicken wire), they are well worth seeing - and cautiously sniffing.

One of the greatest challenges to the mushroom sniffer is to develop a vocabulary to help categorize the sometimes subtle variations. Different mushrooms may smell fruity (though it's often hard to name the fruit), garlicky, spermatic, floury, cucumbery, bleachy, or like a "provocative compromise between red hots and dirty socks" (mushroom writer David Arora's description for the prized edible matsutake mushroom, Armillaria ponderosa).

Perhaps a class in wine-tasting would help. But I'd rather be spending my winter in a damp burgeoning forest sniffing the natural odors of mushrooms.

If you want to learn more about mushrooms (including how to recognize edible and poisonous ones), there are numerous books available, outstanding among them Mushrooms Demystified by David Arora (published by Tenspeed Press). Or go to a program or a foray with the Mycological Society of San Francisco, (415)759-0495 or visit www.mssf.org

But do gather mushrooms only where legal. Most public lands in and near the Bay Area are off-limits, and those that do permit gathering have specific restrictions. The following are favorite rainy-season mushrooming areas, but call first to find out the rules for each.

Jackson State Forest (Mendocino County), permit free but required, (707)964-5674.
Lands End (Golden Gate National Recreation Area - San Francisco), one pound per day, (415)556-8371;
Point Reyes National Seashore (Marin), (415)663-1092;
Samuel P. Taylor State Park (Marin), five-pound limit;
Joaquin Miller Park (Oakland), no specific restrictions, (510)482-7857;
Salt Point State Park (Sonoma County), (707)847-3221 or http://cal-parks.ca.gov/north/russian/spsp248.htm

Don Forman