The mushrooms in the photograph above are all growing on wood, which is one of the many diagnostic traits experts use to identify various mushroom species. This might surprise you: The color of the mushroom--a trait most people notice first--isn’t necessarily the most important characteristic used to identify a particular species of mushroom, no more than the color of someone’s hat automatically identifies the name of the person wearing it.

Some mushrooms grow only on wood, while others grow only in grassy areas. Some species grow only around certain species of trees. Some mushrooms, believe it or not, actually grow on the caps of other mushrooms.

Although color is certainly important, habitat often is a more important characteristic to note when identifying mushrooms.

Realize that mushroom colors can vary within the same species, depending on age and environment. Simply put: Color is merely an additional trait to consider among other, equally important traits.

The Defining Traits of a Mushroom

OYSTER MUSHROOM Pleurotus ostreatus

What’s under the cap of a mushroom is of major importance. Some mushrooms, such as the common Oyster Mushroom (Pleurotus ostreatus), have blade-like “gills” on the underside of the cap. Others, such as the boletes described on the introductory identification page, have pores instead.  Oyster Mushrooms also grow only on wood, sometimes sprouting from the buried roots of trees.

Among the important diagnostic traits one might consider, the color of the Oyster Mushroom is an indecisive feature. Why? Oyster Mushrooms in Illinois can range from nearly snow white to dark brown to steel gray, but often tan or beige.

Many mushrooms, including a few great edible species, are difficult to assign to obvious categories. The Chicken Mushroom (Laetiporus spp) can appear as a lumpy but colorful growth on or around wood, or it can form shelf-like brackets that eventually turn bone white in age.

Scientific keys created for fungi, where a mushroom in hand must eventually be narrowed to either one species choice or another, can frustrate beginners, especially when none of the sensible choices leads to sensible answers. But remember that scientific keys are nothing more than mankind’s effort to organize nature’s billions of unique features, sometimes assembling together things for no other reason than because they seem similar, which can be as troublesome as associating a violin with violence simply because a dictionary displays them on the same page.

Here’s a quick checklist of basic, defining traits of any mushroom:

1. Where, exactly, was it growing?

2. Does it have a cap and stem--and what’s under the cap?

3. What color are the spores? (See: How to Make a Spore Print)

4. What color is the mushroom--and on what parts?

Go where mushrooms grow.