In pursuit of giant puffballs 

Immature giant puffballs (Provided photo — University of Wisconsin, Green Bay)

Puffball is the generic name for a large group of mushrooms with similar characteristics. They come in many sizes and are usually spherical or globular in shape. 

Puffballs are distinguished from other mushroom groups by the fact that they lack many of the features or characteristics that other common mushrooms possess. A puffball has no stem. It has no cap. And no external gills. All of the spores are produced inside of the fruiting body. The most common way in which they release their spores is through impact: the external force of rain or falling debris landing upon them or of animals stepping on or brushing against them, thereby compressing and/or breaking the peridium, the protective layer that encloses the spore mass inside the fungus. When that happens, as the name puffball implies, the spores are ejected in a large puff.

The puffball mushroom I’m going to focus on in this column is the giant puffball, Calvatia gigantea, undoubtedly the superstar of all puffball mushrooms. Calvatia is derived from two Latin words: calvus, which means bald, and calvarium, which translates as the dome or braincase portion of the skull. Gigantea, of course, means gigantic. Calvatia gigantia, therefore, denotes an enormous bald head. 

Giant puffball mushrooms characteristically grow to be 8 inches to a foot across or larger — occasionally much larger! I’ve read about giant puffballs weighing 25 pounds or more. And according to a 2006 entry in Cornell University’s Cornell mushroom blog, “the largest ever recorded giant puffball was eight feet, eight inches in diameter and weighed forty-eight pounds.” (blog.mycology.cornell.edu/2006/10/26/giant-puffballs-calvatia-gigantea

When immature, the exterior of a giant puffball mushroom is smooth and white. The inside, or gleba, is white, solid and fleshy. But like all puffball mushrooms, as it matures, the giant puffball transforms into a spore sac, a mass of powdery spores. The spores are released when the sac becomes cracked or broken. The previously mentioned Cornell blog entry goes on to say that “a single ten-inch giant puffball has as many as 7 trillion (7,000,000,000,000) spores. If each of those spores grew and yielded a ten-inch puffball, the combined puffball mass would be 800 times that of the earth.” 

Immature giant puffball cut it in half from top to bottom (Provided photo — University of Wisconsin, Green Bay)

Giant puffballs, like most mushrooms, do best when there is adequate moisture and above freezing temperatures. Like anything else that grows, they can have good seasons or they can have bad seasons. Judging from what I’m seeing and hearing locally, it’s shaping up to be a pretty good giant puffball foraging season. Evidently, the deluges of rain that we’ve received recently have roused the giant puffball spores into action.

For those of you who’ve never seen or perhaps even heard of giant puffballs, seeing one, or a grouping of several for the first time, can be a somewhat exciting and whimsical experience.

They grow only on the ground, not in trees and not on downed logs, and often look decidedly out of place. You may notice what appears to a soccer ball near the fence in your neighbor’s yard, or you might come upon what, at first, looks like a volleyball amid the fallen leaves and plant debris at the edge of a natural clearing in the woods. When the object in question instead turns out be a bulbous white mushroom the size of a pumpkin, you tend to remember it. Simply stated, once you’ve actually seen one, it becomes pretty darn easy to identify others.

Given their unique and impressively large appearance, along with the fact that they’re edible (Did I mention that they were edible?) and that many mushroom and wild foods foragers consider them to be the easiest of all edible mushrooms to identify, you have a recipe for a very in-demand mushroom. 

While the giant puffball may be one of our region’s most unmistakable species, when foraging, accurate identification is absolutely vital. Only young, immature puffballs are edible. The interior tissue must be soft, bread-like and uniformly white. Once the flesh changes color and/or becomes mushy, spores are present. The mushroom is past its prime, no longer edible and can cause digestive problems. 

If you think you’ve found one of these sizeable, delicious mushrooms, the first thing you need to do is cut it in half from top to bottom. The inside flesh should be thick, firm, spongey and pure white through and through. Don’t eat anything that is beginning to turn off-white or that has yellow, brown, black, purple or any other discolorations or any evidence of the silhouette or contour of a gilled mushroom at the center. If gill structures are present, the mushroom is a toxic species. It is NOT a puffball. If any discoloration is present, the mushroom is too mature to eat. 

However, if you do find a giant puffball that’s passed its prime and no longer edible, you might want to consider returning to the same area in a week or so, at which time you may find one that is edible. Giant puffballs often reappear in the same place for several weeks and for several years running. 

Keep in mind that rare allergic reactions have been reported, although they are usually minor. A good rule of thumb when trying a new food is to eat only a small portion at first and wait before indulging in larger quantities.

Giant puffball mushrooms don’t keep well and should be eaten soon after harvesting. 

If you’re interested in mushroom foraging, the first thing you should do is purchase a field guide to North American mushrooms. Local libraries typically have one or more on hand, but buying your own copy is certainly prudent. Pocket-size editions with color photos are easily carried and help assure positive identification. Focus your attention on just a few preferred species until you’ve become familiar with them. Then get to know them well. 

Happy foraging.


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