Gyromitra is the name of a genus of mushrooms that are common in the spring and summer around North America, and the non-Latin names associated with the different species of Gyromitra are telling as to their appearance and habitat: the snowbank false morel and the brain fungus are the common monikers for two of the most common Gyromitra mushrooms, Gyromitra gigas and Gyromitra esculenta, respectively.
 
DISCLAIMER: Gyromitra mushrooms are poisonous (with qualifications), and Gyromitra esculenta is quite capable of killing you. More on that later. Long and short of the matter, however, is that Gyromitra esculenta is a potentially deadly mushroom.
The signature of Gyromitra mushrooms is their warped, folded caps, which are smooth and rubbery and often look like malformed brains or a piece of putty that’s been in the hands of an anxious toddler for a little too long. They have stems as well; sometimes those stems are hollow like a morel, other times the stem is stuffed with fibrous material. In almost every case, the stem will be less colorful than the cap of the mushroom; in the case of Gyromitra esculenta, the cap is a lurid red-brown color and the slender stem tends to be dark brown with hints of a reddish hue. Gyromitra gigas, by contrast, has an ochre-orange cap with a whitish stem that is thick and chunky.

The Dubious Reputation of Gyromitra Mushrooms

Mushrooms in the genus Gyromitra are somewhat controversial in the mushroom hunting community; some people eat them with gusto, others urge extreme caution, and many people proclaim they’re simply too dangerous to be trifled with, full stop. I fall into the latter category for the most part: although I have eaten Gyromitra esculenta in the past, I would be very hesitant to consume it (or its relative, Gyromitra gigas, which is sometimes called Gyromitra montana and/or Gyromitra korfii, depending on distribution) in the future.

Gyromitra mushrooms are interesting to me, however, because they are extraordinarily beautiful in a weird sort of way, and they are also an excellent indicator species for morel mushrooms, which is one of the finest edibles in the world of wild mushrooms. If you are on the hunt for morels, spotting Gyromitra esculenta or Gyromitra gigas is a good clue that you’re in the right habitat, although you might be a week or two early for the springtime morel bounty.
In addition, the unusual chemical profile of Gyromitra mushrooms and its interaction with the human digestive system is fascinating to me, even if it’s a little creepy. Gyromitra mushrooms contain a toxin called Gyromitrin (original, right?) that, when combined with the digestive juices in the human belly, transforms into a deadly poisonous toxin called monomethylhydrazine (MMH for short). MMH is a charming substance that is used as a component in rocket fuel. It also can kill you. For this reason, most folks don’t eat Gyromitra mushrooms, even though the process of cooking can burn off the Gyromitrin, ultimately rendering the mushrooms edible.
Gyromitra esculenta is listed as poisonous in most current wild mushroom field guides, and its relative Gyromitra gigas (and G. montana and G. korfii, which are likely the same species that reside in different regions) is usually referred to as suspect. However, this was not always the case; before the Gyromitrin/MMH (rocket fuel) poisoning connection was made, Gyromitra esculenta was widely appreciated for its delightful taste. In fact, the Latin name Gyromitra esculenta hints at its origins; the word “esculenta” means “excellent,” and the mushroom acquired its name on account of the esteem it received for being a choice edible in European societies with traditions of foraging for mushrooms.
Indeed, my own opinion of the flavor of Gyromitra esculenta is quite high; I found the mushroom to be much akin to a morel; meaty, a little chewy, and savory in the way that makes my mouth water every time I think about it. That said, I will probably never eat them again, just to be on the safe side.

 How to Cook Gyromitra esculenta and (Probably Not) Die

If you absolutely must try Gyromitra esculenta before you die, it should be cooked very thoroughly. This is how I was instructed to prepare Gyromitra esculenta, and as I mentioned I did not experience any ill effects from it.

• Parboil the mushrooms for a few minutes, being incredibly careful not to inhale the fumes. As the mushrooms boil, the Gyromitrin in them evaporates off. There have been some instances in which chefs got very sick after simply inhaling Gyromitra fumes. If you’re inside, open the windows and run a fan. Even better (this is the method I used) boil them on a very windy hillside, and stay upwind.
• Cook like crazy, using medium-high heat. Again, avoid the fumes.
• Salt, and eat very sparingly. When I tried them, it was not within the context of a dish. Given how good they were, I was glad I had to consciously decide to consume each little morsel of mushroom.

Gyromitra Habitat, Distribution, and Macroscopic Features

Gyromitra esculenta and Gyromitra gigas can be found in most places around the United States and Europe. It is typically an early springtime mushroom, and often grows in the mountains, where large snowdrifts melt and leave the ground wet when the weather warms. As a consequence, Gyromitras are often tucked in at the base of small hillocks or directly below spots where snow tends to accumulate; I have rarely found Gyromitra mushrooms of any sort on level ground.
Gyromitra can be found around the U.S., including my current home (the North Carolina Piedmont), the Rocky Mountains, the Sierra Nevada in California, the Cascades in Oregon and Washington, and (evidently, I haven’t seen it myself) in the Midwest. They are particularly common at high elevations. Naturally, the term “spring” in those habitats is relative to temperature and moisture levels, and most of the large fruitings of Gyromitra I have personally found were in late April and through the month of May. At lower elevations, they come much sooner; March and April primarily.
Gyromitra is most recognizable by its warped and rubbery cap, which tends towards reddish or tawny. The folds in the cap are not deep pockets, rather they have the appearance of slowly melted wax that droops over time from a candle. As noted earlier, the stems can be either hollow or full of fibrous material, but in any event the stems and caps are rather brittle; they bend a bit before breaking, but they do not “mush” like some fungi do. There are no discernible gills on Gyromitras, either. The spores on these ‘shrooms form in the folds and on the surfaces of its wrinkly, crinkly, weirdo cap, and so it’s difficult to get a spore print from these puppies.

These mushrooms are worthy of concern for beginners, because they can be mistaken for morel mushrooms on account of their “brain like” appearance. However, if you’ve ever seen a morel up close and personal, you would not mistake it for a Gyromitra. Nonetheless, if you’re planning to hunt for morels, study images and descriptions of Gyromitra like your life depends it. Not to be an alarmist, but it quite literally could.