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The Amateur Mycologist #11 - Calvatia gigantea - The Giant Puffball

The Amateur Mycologist #11 - Calvatia gigantea - The Giant Puffball

These posts are not for foraging. They are intended for entertainment and educational purposes only. These posts are not a field guide nor comprehensive in any way - their accuracy is not assured in any way. Do not eat wild mushrooms unless you are a professional or have a wealth of personal experience with a specific species. Do not make any foraging decisions based on these posts.

These Posts Contains No Information Regarding Edibility Or Toxicity


The first species specific post we did was of the common puffball, Lycoperdon perlatum. A couple of posts ago we talked about B.edulis and @foodisfree asked whether other mushrooms get bigger than the sometimes very large B.edulis and its cousins.

Well, @foodisfree, here's your answer. A mushroom like almost no other on earth - Calvatia gigantea - or the Giant Puffball.


Above is C.gigantea. These things can get positively enormous - ball shaped and over a meter in diameter, sometimes over 40 pounds each. There are stories of C.gigantea being mistaken for an errant sheep. C.gigantea pops up out of the earth, seemingly out of no where, often growing in grassy fields, or in deciduous forests, sometimes alone and sometimes in groups.

Like its relatively tiny cousins L.pyriform, all giant puffballs are composed entirely of gleba - meaning they have none of the "normal" fungal structures. Instead the mushroom's entire flesh will eventually deteriorate into spores. The flesh starts off perfectly white and firm. But eventually a transition begins and the flesh starts turning yellow and eventually brown. In the end, the perfect, large puffball breaks down entirely into a huge pile of brown spores.

C.gigantea may have a perfectly white outside skin, or sometimes have a darker colored skin. Take for instance the smaller specimen I found in a NYC park some years ago.

You can see here that the mushroom has discolored skin, almost a very light brown. Also, if you take the penny for size reference, you'll also see that this is not a very large specimen. I likely picked it early in its development. Nonetheless, this mushroom was larger than my closed fist, which made it very unlikely to be anything but a giant puffball or its relatives.


The way to be certain is to cut it the mushroom in half. Like the larger wikicommons pictures above, the bifurcated mushroom reveals only pure white flesh, undifferentiated by either color or, most importantly, the incipient structures of a future gilled mushroom.



A fully grown C.gigantea is perhaps the most foolproof mushrooms in the world to identify. First, make sure the mushroom is larger than an adult male fist, at least. Beyond that there are only two tests C.gigantea has to pass.

  1. Cut the mushroom, no matter its size, in half. The flesh should be UNDIFFERENTIATED, meaning there should be no sign of any gills or cap hidden inside the mushroom under a universal veil.

  2. The flesh needs to be pure white. Any yellow, brown or purple means it has already begun the sporification transition.




C.gigantea is an incredible wild mushroom. One of the easiest to identify and also one of the more astounding natural creations you are ever likely to encounter. Count yourself as lucky if you come across one and take photos so non-mycology buffs believe you!


Macroscopic Features:

  • Cap/Flesh = Usually looks like a ball, ranging from softball sized up to beach ball sized. Sometimes irregularly shaped, but always larger than an adult male fist. Anywhere from 4in to 27 inches or more in diameter (10 to 70+ cm). Outside ranges go as high as 59 inches (150cm) in diameter. Can weigh upwards of 44lbs (20kilos) for largest specimens. Flesh begins a perfect, firm white, undifferentiated, with no incipient gill or cap structures. Turns yellow or green-yellow then eventually brown. Often has a small tapering near the base of the mushroom where it meets the ground, possibly a small cord of material there as well. When mature, outside skin peels off and all flesh turns to brown spores which are easily made airborne.

  • Spore surface = N/A - All Flesh matures into spores.

  • Stem ("stipe") = N/A

  • Spore Print = N/A - spores are brown.

  • Ecology ("How it grows.") = Saprobic - grows solitary or sometimes in small groups. You can find it all over on the ground - sometimes in fields, or at the edges of a path (like I did). Late summer or early fall mushroom.

  • Distribution = East of the Rocky Mountains and Europe. Sometimes UK.

  • Other Traits = Mushroom flesh/dust may anecdotally have blood clotting properties. Always bifurcate the mushroom, no matter its size, to make sure it is not a baby Amanita and to make sure the flesh has not begun to spore.

Disclaimer 2

The only 100% way to avoid being hurt by a wild mushroom is not to eat a wild mushroom. These posts are not field guides - they are intended for the mycology enthusiast, not the forager. If you want to forage mushrooms there are professional resources available to that end online as well as local mycological societies all over the world which you should connect to for guidance.

For The Online Mycokey program look Here

For a Glossary Of Relevant Mycological Terms, Micheal Kuo's Website Provides


Information Sources: http://www.first-nature.com/fungi/calvatia-gigantea.php http://www.mushroomexpert.com/calvatia_gigantea.html https://en.wikipedia.org/wiki/Calvatia_gigantea#Description http://powo.science.kew.org/taxon/urn:lsid:indexfungorum.org:names:265958 http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=265958 http://mushroom-collecting.com/mushroompuffball.html http://herbarium.usu.edu/fungi/FunFacts/Funfacts.htm

Photo Sources: [1]© Hans Hillewaert / , via Wikimedia Commons [2]By Maerian Own work CC BY-SA 4.0, via Wikimedia Commons [3]By H. Krisp Own work CC BY 3.0], via Wikimedia Commons [4]Michael Gäbler CC BY 3.0, via Wikimedia Commons [7]Pavel Ševela CC BY-SA 3.0, via Wikimedia Commons.jpg)

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