Gyromitra caroliniana

by Barbora Batokova • Updated April 7, 2023

The first time I found this mushroom I squealed with excitement. It was the end of March and it’s been months since I’ve found anything exciting in the woods, let alone a terrestrial mushroom! Known as the Big Red or the Carolina False Morel, this is one of first spring mushrooms to appear after snowmelt, signaling the start of morel season. Many morel hunters encounter it in the woods and if you’re one of them or aspiring to be one, this mushroom is worth learning. It resembles true morels, but it is part of the Gyromitra genus, which contains some highly poisonous mushrooms. I’ve found G. caroliniana in the same exact spot by a giant fallen tree in Frick Park for two years in a row now. They are beautiful, intriguing mushrooms that can grow to massive sizes, much larger than true morels. A specimen weighing 23 pounds was reported in Missouri.¹

Etymology
Taxonomic History
Ecology
Description
Distribution
Similar Species
Edibility and Taste
Cuisine
Medicinal Properties
ID Table

Etymology

The name Gyromitra comes from gyro meaning “round” and mitra meaning “turban” or “headress,” which is clearly referring to the large, intricate cap of the mushroom. The specific epithet caroliniana refers to the Carolinas, the two states in the United States where it was first collected scientifically.²

Taxonomic History

It was originally described in 1811 by a French botanist Louis Augustin Guillaume Bosc as Morchella caroliniana in Dissertation on Some Species of Fungi from the Southern Parts of North America and sanctioned by Elias Fries in 1822 in Systema mycologicum (see the original page).³ In 1871, Fries transferred it to the Gyromitra genus. In the early 1970s, the original description by Bosc was deemed ambiguous and it was redefined based on five specimens collected from Lorton, Virginia in 1942.⁴ Finally, a 2013 DNA study by Methven et al. established five subgenera for the genus Gyromitra, one of them being Caroliniana that contains the type species Gyromitra caroliniana (Bosc) Fr. and Gyromitra brunnea (Underw.).⁵

Ecology

This mushroom grows early in the spring, often right after snowmelt, in hardwood forests, usually by rotting stumps. In the above photo, you can still see some remnants of snow, an April Fool’s Day overnight delivery by the famously variable Pittsburgh weather. There are three fruitings in the above photo.

Growing singly or in loose groups in hardwood forests, this mushroom is officially saprobic, but it does exhibit some mycorrhizal tendencies, and it may integrate both ecological lifestyles in its lifecycle.¹ It loves rich soil, and it is often found near rotting stumps and downed trees. I have always found it at the end of March in western Pennsylvania.

Description

These mushrooms look like tiny trees inside and out. The deeply wrinkled cap looks like a treetop and when sliced open, it resembles tree branches. The white stipe has a wide base that is reminiscent of giant trees.

The red-brown cap is heavily and deeply wrinkled and nearly spherical to roughly elliptical in shape. It has a smooth, bald texture and its size can range from 5-20 cm high and 6-13 cm wide. It is tightly affixed and ingrown with the stem, so very little of the head tissue hangs down over the stipe. When you slice it open, you can see the chambered interior that resembles a cauliflower or a tree: the whitish, brittle flesh forms dense vertical locules (chambers), forming branches to the points of attachment. This is the best way to tell a true morel from a false morel: true morels are always hollow inside.

The white stipe is massive (it can be up to 2-11 cm thick and 4-10 cm long), and gets significantly larger toward the base, almost like a giant tree. If you pick up the mushroom, you will often take the surrounding soil with it (see photo below). The stipe has a felt-like surface and is ribbed inside.

Distribution

After I picked up this mushroom, a large chunk of the soil came with it, thick with mycelium.

Based on current research and iNaturalist observations, this species only grows in the United States, where it is widely distributed from Kansas, Oklahoma, and northern Texas eastward. The northern edge of its range are the southern Great Lakes. It is common in the south and in the Mississippi and Ohio valleys.

Similar Species

Since G. caroliniana only occurs in North America, the above photo only compares similar species occurring in North America.^{11 and 12}

Part of the Caroliniana subgenus, Gyromitra brunnea, commonly known as the gabled false morel, is extremely variable in appearance, but it can be distinguished from other Gyromitra species by its lobed cap, which is often gathered into two or three points, creating a saddle-shaped appearance. The stipe is much smaller than G. caroliniana—only up to 5 cm thick. It is also found under hardwoods, often near stumps and downed trees, in spring and it is widely distributed in the Midwestern and eastern states of North America. It is conditionally edible (see Edibility and Taste below).

Gyromitra esculenta is the closest lookalike and the most dangerous one as it contains high levels of toxins. It can be distinguished from G. caroliniana by its convoluted reddish brown cap that is shaped like a brain (horizontal oval) and the fact that its stem is not massive in proportion to its cap. In addition, it fruits in sandy soils under coniferous trees.

Gyromitra korfii/gigas, commonly known as the snow morel, is also found under hardwoods in the spring east of the Rocky Mountains and in Europe. It differs from G. caroliniana based on its squarish light tan cap and a stem that develops broad ribs or waves—it is much “airier” than G. caroliniana. It is conditionally edible (see Edibility and Taste below).

Edibility and Taste

G. caroliniana mushrooms are conditionally edible provided you prepare and cook them properly. However, because they belong to the Gyromitra genus that contains G. esculenta that is responsible for many poisonings, some resulting in death, they remain controversial and only for expert mushroom hunters.

The Gyromitra genus is controversial to say the least. It has a bad reputation due to numerous deaths, hospitalizations, and liver damage that are mostly caused by improper preparation of G. esculenta, which contains gyromitrin, a toxin and carcinogen. Upon heating or when digested in the body, gyromitrin is readily hydrolyzed to the toxic compound monomethylhydrazine (MMH), which acts on the nervous system and is used as a propellant in some rocket fuels. Symptoms from MMH poisoning occur 8-12 hours later, or, rarely, 2 hours later, and resemble poisoning from amatoxins. Symptoms include “a bloated feeling, nausea, vomiting, watery or bloody diarrhea, abdominal pains, muscle cramps, faintness, loss of coordination, and in severe cases, convulsions, coma and death.”⁶ Some patients may also develop hemolysis and hepatic diseases of moderate severity and carcinogenesis may also occur.⁷With medical help, recovery from MMH poisoning can occur within hours.

However, unlike amatoxins, which are thermostable and resist changes due to heat, gyromitrin can largely be removed by parboiling. If you boil the mushrooms twice, rinsing them and changing the liquid in between, more than 99% of the gyromitrin will be released into the water, making the mushrooms safe to eat without acute toxicity. Because gyromitrin is not stable and begins to break down spontaneously at room temperature, drying is also one way to reduce toxicity, although it's not as effective: between 30-71% of MMH still remains in [G. esculenta] mushrooms after drying and “dried G. esculenta mushrooms are commonly used as food even though they may still contain 3 mg/kg of gyromitrin.”⁸

This is how G. esculenta and other Gyromitra species have been eaten for centuries in Europe. In the Czech Republic, G. esculenta was sold in markets until 1950's, but occasional poisonings after eating this mushroom eventually ended that practice.¹⁰ Now, Czech mushroom field guides caution that all Gyromitra species may contain toxins and therefore recommend parboiling before preparing any dish. In Finland, you can buy G. esculenta both fresh and dried in stores. In Russia, G. esculenta and other Gyromitra species have always been considered conditionally edible after parboiling.

The edibility of Gyromitra species is determined by two major aspects:

Various Gyromitra species have varying levels of toxins and, within each species, levels can vary by local genetic strain.
Proper preparation (parboiling or drying) reduces the amount of toxins.

Technically, you could detoxify G. esculenta to get rid of the MMH (and people in many countries do), but I would strongly advise against it. I have never eaten it myself and frankly, it’s just not worth the risk that could result in your death, because levels of toxins can vary and you can never know if you’ve gotten rid of all toxins.

However, G. caroliniana, G. brunnea, and G, korfii/gigas are safe to eat, even without parboiling. Michael W. Beug, Ph.D., who serves on the North American Mycological Association (NAMA) Toxicology Committee, does an excellent deep dive into the edibility of Gyromitra species. I highly recommend reading the entire piece, but in conclusion, he writes that “G. caroliniana and G. brunnea are probably no more dangerous to consume than Morchella species,” which are also toxic when raw.Furthermore, he reports that “there is also no information in the NAMA database about poisonings from the two species.”⁵

In conclusion, G. caroliniana is edible, but must be cooked well.

Cuisine

G. caroliniana mushrooms have a tough texture and are great for gratins. Check out my Gyromitra Gratin with Garlic Mustard recipe.

Even though G. caroliniana (or G. korfii/gigas, G. brunnea, G. montana) can be cused without parboiling, it safer to do so. Forager Chef Alan Bergo points out that G. korfii and G. montana are known to be ok to cook without boiling, but the “cooking” must be thorough and long.⁹ So just to be safe, just parboil them for 15-20 minutes anyway. He also has a great write up on cooking false morels that goes into much greater detail about cleaning, preparation and cooking, along with basic parboiling instructions.

Medicinal Properties

Frankly, after the exhaustive write up about gyromitrin and MMH, there’s not much left to say about the potential medicinal properties of this mushroom! 😂 Jokes aside, a lot of the research focuses on the toxicity of these mushrooms and I have not come across any significant medicinal properties.

ID Table

	Scientific Name	Gyromitra caroliniana
	Common Name	Carolina False Morel • Big Red
	Edibility	Conditionally edible
	Ecology	Saprobic and mycorrhizal
	Grows with	Hardwoods
	Distribution	United States east of TX, KS, OK
	Cap	Spherical • Up to 20x13 cm • Smooth and deeply wrinkled • Red-Brown
	Hymenium	N/A
	Stipe	Very thick, getting wider at the base • Up to 10 cm tall • Up to 11 cm thick • White
	Flesh	White, brittle, and chambered
	Odor & Taste	Not distinctive
	Spore Print	White