May is Morel Month in Michigan (E2755)
November 10, 2015
Don't go into the woods without this priceless help in identifying edible morels and those not recommended for eating. Michigan is famous for its morel lands and this booklet will help you identify safe morels and the 8 species unsafe for eating. Revised 2016
What is a morel?
Morels are often called mushrooms, a common name for large, fleshy fungi. Morels are fungi, and for many years fungi were classified as plants. Fungi are similar to plants in growth habit: they are immobile organisms. Fungi notably differ from plants in lacking chlorophyll, the chemical that green plants employ to absorb sunlight and transform carbon dioxide and water into carbohydrates. Fungi obtain carbohydrates by decomposing organic matter such as wood and leaf litter or by obtaining them directly from plants as parasites or mutualists. When a mushroom is lifted out of the soil or rotting wood substrate, whitish-brown cobweblike filaments are visible. The filaments are the vegetative body, the structures through which they absorb food from the substrate. The individual filaments are called hyphae and the mass of filaments is called the mycelium. The hyphae secrete enzymes to break down organic matter and then absorb the nutrients. Since the 1970s scientists have considered fungi to be distinct enough from plants to be placed in their own kingdom, the Mycota. DNAbased research has revealed that fungi are actually more closely related to animals than to plants.
Mushrooms produce spores rather than seeds for reproduction. Mycologists (scientists who study fungi) separate fungi into classes on the basis of the way the spores are produced. Morels produce their spores inside a microscopic structure resembling a cylindrical sack called an ascus (plural asci). The asci stand on end and line the interior of the pits on the head of the morel. The mature spores are shot out of the terminal ends of the asci into the surrounding breeze to be carried great distances. Because the spores are in an ascus, morels are classified as Ascomycetes.
Most other mushrooms — including the common white button mushroom, the portobello, the shiitake and the porcini - produce their spores on the top of a microscopic club-shaped structure called a basidium; these mushrooms are Basidiomycetes. The spores are also shot into the breeze. We can sometimes see the microscopic spores when the cap of a mushroom deposits thousands on a nearby leaf or mushroom cap. They appear as a fine, colored dust.
Most fungi are called by their scientific names. Relatively few fungi possess common names, and these common names are notoriously unreliable. “Beefsteak,” for instance, can refer to either the false morel Gyromitra esculenta or the wood-rotting shelf fungus Fistulina hepatica. This booklet lists some of the common names with which you may be familiar, but we do not pretend to have a comprehensive listing. You are encouraged to learn the scientific names. Scientific names consist of two parts. The first part is the name of the genus: Morchella in the case of the true morels, Gyromitra and Verpa for the false morels. The second part is the name of the species, the specific epithet. The specific epithet never appears alone but is always preceded by the genus name or abbreviation: thus the black morel is Morchella elata or M. elata. Because scientific names come from Latin or Greek, they are always italicized or underlined. They are used the world over, so a scientist in Israel or Russia will know what you mean when you say “Morchella elata.”
Where do I find morels?
Morels, like all fungi, must absorb their food from their surroundings. Knowing what sort of habitat a morel prefers gives us a better chance of finding it. Morels are less finicky than many mushrooms, with the consequence that one might run across a morel just about anywhere. Morels are believed to occur in every county of Michigan. Usually morels are found in forests and areas with scattered trees. Beech-maple or oak forests with a variety of spring wildflowers and wild leeks growing on the forest floor are good locations for morels. Forests where aspen, ash, tulip poplar or elms are present may yield large crops. MSU Extension bulletin E-2332, Identifying Trees of Michigan, is available to aid in your morel hunting. Often old orchards of fruit trees (especially apple, pear or peach) that are not being sprayed with fungicides have reliable crops of morels. Burned areas of all sizes from a campfire to a forest fire frequently produce abundant crops. Occasionally morels fruit in the first year after fresh firbark mulch has been placed in a landscape. Morels even occur in the sand dunes and open grassy meadows along the Great Lakes, but such morels remain gritty after cleaning and cooking. Recently logged areas are not reliable collecting locations in Michigan.
Advice from successful morel hunters includes the following: “look first for a stand of aspen,” “in young second-growth hardwood forests,” “near a dead or dying elm,” “in old orchards,” “in the charred ash of last year’s forest fire,” “in a stand of ash trees,” “wherever bracken fern grows,” “follow the ravines” or “near spruce stumps.” The truth is that morels are where you find them. If this list seems discouragingly broad, you could do worse than to start your investigations with elms. Recent research has shown that morels frequently can form mycorrhizae with elm trees. In other words, the morel and the elm are capable of forming a mutually beneficial relationship, in which the fungus receives nutrients from the roots of the tree and, in turn, helps the roots obtain minerals from the soil.
When should I look for morels?
Morels are one of the few edible mushrooms to fruit in the spring. Most other edible mushrooms are found in the late summer to late fall until the snow flies. Start to look for morels in the early spring as the soil warms up. The morel season generally begins in the south and progresses 100 miles or more north per week. In any region, look earliest in the year on south-facing slopes, then westfacing slopes, then east-facing slopes, then north-facing slopes. Ridgetops and flatlands are scattered in here and there, depending on the weather. Individual species differ in their time of fruiting as noted below. In general, the black morels show up first, then the gray and yellow morels, with the half-free morels mixed in the middle.
The most important factor is probably rainfall amount, followed by temperature. It must be wet enough and warm enough for the morels to emerge. Mushrooms are about 90 percent water, so if there’s no rain at the right times, there are not likely to be many morels. However, too wet or too hot can be just as bad for fruiting.
Most veteran morel hunters have specific signs of nature (phenology) they look for to know when to start hunting morels. Some look for “oak leaves the size of a squirrel’s ear” or “maple leaves the size of a mouse’s ear.” Others look for blooming of serviceberry or wild plums. Many look for morels as the asparagus begins to pop up in their gardens. Still others look to wildflowers — when the hepatica, arbutus or white violets are flowering.
Where and when should I look for morels the next year?
Keep careful notes about when and where you find morels; they will often occur in the same spots at the same time (or under the same conditions) in later years. The most reliable place to find abundant morel fruitings is under elm trees the spring after a tree has been killed by Dutch elm disease. The second year after the tree dies, the yield may decrease to 10 to 30 percent of the first year’s yield. The third year’s yield may be 10 to 30 percent of that. There are exceptions to this rule, of course. Yields under living apple trees, ash, cottonwood or other trees are usually lower than under elms but are fairly consistent from year to year and are more dependent on moisture than on the condition of the trees.
Does it damage future morel crops when I pick morels?
Any mushroom, the morel included, is only the reproductive structure of the living organism. Most of the fungus is underground, and the mushroom is only a small portion of that colony, analogous to the fruit of a plant. It will not kill or harm the fungus to pick the morel. For mushrooms with gills, an important step in verifying that they are not poisonous species requires lifting the entire mushroom stalk out of the soil for inspection. A higher yield of morels may occur during the next few days at a spot if the morel stalk is cut at the ground when picked rather than pulled from the ground, if the weather is conducive. However, this phenomenon influences only the area immediately near the individual stalk. Reduction of the total morel crop following years of harvesting has not been demonstrated.
Is it safe to pick mushrooms?
No fungi are dangerous to touch, not even the deadly poisonous species. You will want to take some precautions, the same precautions you would take any time you go into the woods. It is important to:
1. Bring a compass and a map. Learn how to use the compass and take your bearings before entering the forest. Morels rarely cooperate by growing right along the trail and, if they do, someone else probably picked them already. You will probably need to leave the paths and plunge into the woods.
2. Prepare for ticks, mosquitoes, blackflies and other biting insects. In Michigan, the odds of encountering deer ticks that can carry Lyme disease are slight in the Lower Peninsula. In Michigan’s Upper Peninsula, the odds increase as you travel east to west. Deer ticks must feed for 24 hours to transfer enough of the Lyme bacteria to cause an infection. Deer ticks are very small, have eight legs and do not have white markings. The most important areas for application of a tick repellent are the tops of the shoes, socks and pant cuffs. Check yourself, children and pets for ticks after being outdoors.
3. Learn how to identify poison ivy and carefully avoid touching it while collecting mushrooms.
4. Keep track of time. Allow for enough time to get out of the forest before dark.
5. Carry some water and do not drink from streams or lakes - such water is often contaminated with potentially harmful microorganisms such as Giardia.
6. Dress for the weather; springtime weather in Michigan can be unpredictable.
7. Michigan has only one venomous snake in the Lower Peninsula, the eastern massasauga rattlesnake. This snake does not occur in the Upper Peninsula. This rattlesnake is not as dangerous as its western relatives because of its small size and short fangs. It is a shy, secretive snake that avoids human contact. It occurs in low numbers in certain swamps and marshes. Bites to humans are rare.
It is often difficult to determine which lands are private property and which are public. One way to find out which parcels are private is to use a plat map. Plat maps can be obtained from county MSU Extension offices, Farm Bureaus and county clerks’ offices.
You cannot be harmed by picking fungi but you can be harmed by eating fungi. Never eat a mushroom unless you are absolutely positive of its identity. Relatively few mushrooms can actually kill you. Approximately eight species are lethal out of more than 2,000 species in Michigan, but a poisonous species may be locally abundant. Mushroom poisoning is a decidedly unpleasant experience and never worth risking for the sake of a meal. Spend some time looking closely at each mushroom you pick, and compare it with the pictures in this booklet and a field guide. If you are in any doubt, do not eat the mushroom. Do not eat mushrooms raw, particularly morels. Additionally, we do not recommend eating any species of false morel or lorchel. The beefsteak false morel, Gyromitra esculenta, has been responsible for several deaths in the United States and Europe, and must not be eaten.
Identifying True Morels
The morels and their close allies can be divided into two broad categories, the true morels (edible) and false morels (poisonous). True morels are distinguished by a hollow, cone-shaped to cylindrical cap connected at the base to the hollow stalk. The cap is distinctly pitted (not wavy, wrinkled or folded), and, in most species, there is no break between the cap and the stalk (see figures). Morchella semilibra, the half-free morel, is just that - it has a cap that is half-free from the stalk, with the connection occurring partway up the cap. The lower portion of the cap hangs free like a skirt (see figures). True morels are usually 2 to 6 inches in height with a cream-colored stalk and a cream, tan, gray-brown or black cap. The record size for a true morel in Michigan approaches 17.5 inches tall, 15 inches in circumference and 20 ounces. Annual festival records in Michigan usually reach approximately 9 inches tall. The European record from Sweden is 31.5 inches tall (80 cm). Let’s hope we can break the records this year.
Identifying False Morels, the Lorchels
False morels (sometimes called lorchels) differ from morels in the attachment and ornamentation of the cap. The stalk is attached to the cap at the very top of the cap (not at the base or partway up the cap, as in true morels) (see figures). The cap may be smooth, wrinkled, wavy, ridged or folded, but it is never pitted. There are two principal false morel genera, Gyromitra and Verpa. You are likely to encounter these fungi while hunting for morels, so we have included the common species of Michigan in this booklet, but we remind you that fungi in these genera are probably dangerous and should not be eaten.
Poisoning by the False Morels, Especially the Beefsteak and Related Species
Despite well-publicized warnings of poisonings by Gyromitra esculenta, Gyromitra infula and related species, they are still widely consumed by many people who have failed to be impressed by evidence of their toxicity. Verpa bohemica and Verpa conica are also reported to cause poisoning but are widely consumed. We provide some details about the evidence on poisoning here.
Verpa bohemica and Verpa conica have been proven to occasionally cause gastrointestinal upset and a loss of coordination (such as problems with writing) for as long as 5 hours after eating. Never overindulge. Gyromitra esculenta, the beefsteak, is recognized as an edible mushroom that sometimes kills. It contains the poison gyromitrin, a hydrazone that is changed in the acid stomach into a rocket fuel, monomethylhydrazine. Fresh specimens normally contain a lot of the toxin, although individual mushrooms differ in the amount of toxin. A wide variation in sensitivity to the toxin exists among people. Children have an enhanced sensitivity to the toxin. Gyromitrin is unstable and volatile, and drying greatly reduces the amount of the volatile hydrazines. Well-dried specimens will contain toxin below the level that could cause acute toxicity. Boiling can eliminate much of the toxin, which moves into the cooking water and even the water vapors (steam). These vapors alone can poison the cook in a poorly ventilated kitchen. Also, the poison in the cooking water can be directly absorbed through the cook’s unbroken skin. We never recommend eating the false morels, especially without drying. However, if fresh specimens are cooked, turn the stove fan on high and open the windows, or cook outside. If you decide to take the significant gamble of eating these mushrooms (which we do not recommend), boil fresh specimens for at least 10 minutes, then discard the cooking water, add fresh water and boil for another 10 minutes. Discard the cooking water and dry the mushrooms on a dry cloth or paper.
Regardless of the method of preparation, these false morels are potentially dangerous and may still cause symptoms. Even if symptoms do not show up right away, the toxin accumulates in the body so that a day of eating the mushrooms without poisoning symptoms may be followed by a day with poisoning if a person eats the false morels on consecutive days. Long-term mutagenic and carcinogenic effects are reported in laboratory tests, so children and pregnant women should never consume the false morels.
In the majority of poisonings, the symptoms begin about 1 to 6 hours after eating. Symptoms are gastrointestinal bloating and pain, vomiting, severe headache, and sometimes diarrhea and fever lasting from one day to a week. Some rare poisonings (usually following overindulgence) are reported in the medical literature in which the above symptoms were followed by jaundice, hemolysis, methemoglobinemia, delirium, coma and occasionally death after 24 to 48 hours. We believe that eating these mushrooms is not worth the risk.
Characteristics of Individual Morel Species
It should not be too difficult to match your find with one of the pictures and descriptions included in this bulletin if you are collecting morels in the spring in Michigan. The common species of true and false morels in Michigan have been included for your benefit. There are also many mushroom field guides available at 19 bookstores that will have descriptions and pictures of these and other species. Be aware that field guides are often sold in regions of the world that are different from the region that the guide was written to cover, and other similar species may be included. Always be wary when collecting in unfamiliar locations.
Note that the classification of morel species is changing as we learn more about the morel. There is controversy over exactly what constitutes a species and where the limits of each species should be drawn. Species of fungi are usually based on macroscopic and microscopic characteristics, as well as potential to mate with one another. Are there three species of morels in North America, as some say, or are there 25, as others say? Morels are extremely variable in their color and shape, depending on the conditions under which they form. More than 100 species have been described on the basis of these color and shape variations. We have taken a conservative approach here and may have lumped some species together. For example, no one really knows what Morchella deliciosa is; is it possibly a young form of M. esculenta? And should we consider the forms that grow under tulip poplar or under hickory as separate, undescribed species? These questions remain unanswered for now.
We have also included the false morels in this booklet for comparison. We do not recommend any of them for eating. However, they’re fun to find, and it’s good to know what’s out there in the woods.
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