Everything you've always wanted to know about fungi
Ample rainfall has made this summer a memorable one for fungi fanciers: mushrooms in numbers not seen for years have popped up across the Vineyard, in fields, woodlands, and lawns. Damp, shady sites are the most productive, but few habitats on the Vineyard are mushroom-free. This soggy season offers a fine opportunity for Vineyarders to become better acquainted with these fascinating, much-maligned organisms.
Despite the plant-like habits of fungi (including mushrooms), most contemporary biologists consider them to be more closely related to animals than to plants. A billion and a half years ago, according to one recent study, descendants of some unknown, single-celled creature diverged along two evolutionary tracks. One line, committed to the strategy of using mobility to obtain food, eventually led to today's animal kingdom; the other, adopting the sedentary habits of plants and a plant-like ability to absorb nutrition from the surroundings, gave rise to today's fungi. But even today, fungi and animals share many biochemical and cellular traits that distinguish them both from plants.
Both groups depend at least indirectly on the ability of true plants to convert energy into fuel that living cells can use. Fungi and animals, in their distinctive ways, both make their living from the digestion (sometimes at several removes) of green plants. Fungi return the favor: many soil-dwelling fungi perform helpful chemical tasks for plants, and in general, the many roles fungi play breaking down organic matter and synthesizing chemicals are essential to the persistence of life as we know it.
Something like 1.5 million species of fungi (most of them not yet formally described) inhabit the world, ranging from mushrooms to yeasts to the organism that causes athlete's foot. Only some 15,000 fungal species are classed as mushrooms (and of these, fewer than 170 have been identified on the Vineyard, though this figure surely understates our diversity). But relationships even within this limited mushroom world are complex. Recent genetic research suggests that the basic design for a mushroom probably evolved multiple times, with the result that some superficially similar species are in fact only distant relatives.
It would be easy to assume that a mushroom is an entire organism. In fact, a 'shroom is a temporary organ grown by a fungus solely for reproduction. A mushroom is a fruiting body; if you think of one as an apple, the equivalent of the tree is a hidden, filamentous mass living underground or in decaying wood. These filaments, the actual "body" of the mushroom fungus, can be extensive in sites that offer expanses of undisturbed soil: a single honey mushroom organism in Oregon, estimated to be thousands of years old and sprawling across more than 2,000 acres, has been proposed as the largest organism in the world.
The details of mushroom reproduction are confusing, but the basic plan is this: when filaments of two fungi of the same species meet under the right conditions, they merge and then produce a mushroom that carries genes from both fungi. When mature, the mushroom in turn produces a vast number of spores - microscopic, seed-like structures capable of dispersing on the wind and producing new sets of filaments. The intricate gills, or pores, on the underside of a mushroom cap maximize the surface area available for spore production.
Mushrooms, of course, are most famous for their ambivalent potential as food. A few species are mainstays of fine cuisine (some of these species occur in the wild on the Vineyard), and many more are deemed delicacies by enthusiasts whose hobby is collecting and cooking wild 'shrooms.
Other mushroom species, however, are toxic, with the most virulent dozen or so lethal even in small quantities (again, some of these occur on the Vineyard). The vast majority of mushrooms fall somewhere between these extremes, being mildly toxic or harmless but unpalatable. Unfortunate individual responses, though, ranging from mild discomfort to enthusiastic vomiting, are possible even with "safe" mushrooms.
So unless you're a seasoned student of the natural world operating with expert guidance - more than just an ID based on a field guide - eating any wild mushroom at all is foolish. But mushroom specialists, like hunters and fishers, take great pleasure in learning to find, identify, and eat wild quarry, and as with sports like open-water diving and hang-gliding, managing risk may be part of the appeal of mushroom-hunting. Even timid general naturalists often have a short list of distinctive wild species (three, in my case) they feel comfortable collecting and eating. For the more adventurous, there are clubs, such as the Boston Mycological Club, that bring beginners and experts together for collecting trips in the field.
Photo by Matt Pelikan
For most people, though, looking will be enough. Even casual observation reveals how varied the Island's mushrooms are in size, shape, color, and habitat preference. Highly variable, mushrooms are challenging to identify (the field guide in the Peterson series is the most helpful one I've found). But even without knowing species names, you can begin to learn what types inhabit what niche. And you can easily appreciate the crayon-box colors, odd shapes, and finely cut architecture of this ancient lineage.
Matt Pelikan's monthly wildlife column, "Wild Side," will next appear in The Times on Sept. 11.