Mushrooms bloom on Martha’s Vineyard in autumn

Bitter Bolete (Tylopilus felleus) are quite common here, especially where spruce trees have been introduced. — Photo by Matt Pelikan

The moist fall we’ve had so far hasn’t done much to promote outdoor fun, but one group of Vineyard organisms has been enjoying the weather: our fungi. Fall always features the peak for mushrooms on the Vineyard; this year, conditions have produced an unusually lengthy season for these interesting Islanders, along with robust numbers and diversity.

In evolutionary terms, mushrooms are more closely related to the animals than the plants. Like animals, fungi lack the ability to produce their own energy through photosynthesis, as plants generally do. Instead, fungi produce enzymes that break down organic material, with the resulting simple chemicals being absorbed and used by the fungus cells. By helping break down dead plant matter, fungi of all kinds play a vital role in cycling nutrients through the ecosystem.

While a bewildering variety of life histories can be observed among the world’s 300,000 or so known species of fungi, it’s possible to generalize about the mushrooms in particular. The actual “body” of a mushroom is usually a sprawling mass of thin fibers, which gradually extend themselves through whatever substrate the fungus inhabits. The mushrooms that catch our attention are just short-lived fruiting bodies, analogous to an apple, produced solely for the purpose of reproduction. Once mature, a mushroom releases millions, billions, or even trillions of minute spores, each one capable of producing a new fungus.

Poorly studied on the Vineyard, the diversity of our mushrooms undoubtedly exceeds the fewer than 200 species that have been identified here. Most plentiful in moist environments, mushrooms nevertheless turn up in all sorts of settings on the Island. An observer with sharp, downward-directed eyes can easily spot dozens of species in a day.

Identifying them, though, is a different matter. Unlike most of our plants and animals, many species of mushrooms are highly variable, and it is difficult to pin down a single characteristic, or even a combination of traits, that suffice to identify a mushroom conclusively. Instead, putting a name to these organisms is generally a holistic process, with a wide range of sometimes contradictory information adding up to a probable identification. Even then, there is uncertainty: mushroom taxonomy is a mess, to put it bluntly, and in many cases, currently accepted species probably encompass multiple actual species that simply haven’t been recognized yet.

Size and shape are helpful for recognizing mushrooms, though these vary with age. The color of the cap and spore-producing surfaces, while also variable, are helpful cues, as is the structure of the spore-producing organs (typically gills or pores on the underside of the cap). Even more helpful is the color of the spores themselves. By putting a mushroom cap gill-side down on a piece of paper, you can encourage it to drop spores onto the paper so you can assess the color of the spores themselves, with the result ruling out large numbers of possible IDs. Biologists examine individual spores under a microscope; while this approach is daunting for an amateur, the size, shape, and texture of a spore is a powerful tool for identification. Finally, habitat and host are useful hints: most mushrooms associate closely with one kind of substrate, growing in the soil under spruce trees, on dead hardwood stumps, on living pine trees, and so on.

While most of us were trained at an early age to fear mushrooms, the cultures of the United States and the British Isles are unusual in their loathing of these organisms. In much of the rest of the world, wild mushrooms are a valued food resource, and collecting and eating them a beloved hobby. There is certainly good reason for caution about eating mushrooms: a few species truly are deadly poisonous, causing liver and kidney failure in doses of just a few grams, and at least one of these, the lemon-colored Amanita citrina, is abundant and widespread on the Vineyard. Similarly, a relatively modest number of mushrooms are deemed safe, tasty, and easy to identify with certainty. In between these extremes, mushrooms range from mildly toxic to harmless but fibrous, bland, or otherwise unpalatable. Even “safe” mushrooms can cause vomiting in individuals who can’t tolerate that particular species.

Given the difficulties of identification, it is simply idiotic for a beginner even to taste any wild mushroom. It’s vital to consult authoritative sources, rule out all poisonous species with absolute certainty, and narrow your identification conclusively down at least to a group of related species that are all considered edible. Hence, even many experienced foragers ignore mushrooms and focus instead on berries or other more readily identified plant resources. Personally, I have a list of about a half-dozen mushrooms I feel comfortable collecting and eating, but I get considerable satisfaction gathering these. Whether it’s fish, fruit, or fungus, harvesting and eating a wild resource gives a powerful sense of connection to the environment. So I look forward to expanding my mushroom repertoire — cautiously!

Colorful, varied, useful, and enigmatic, mushrooms are a wonderful feature of a Vineyard autumn. Take advantage of the season to appreciate their elegance and variety.