Appalachia--Science in the Public Interest

MUSHROOMS

by Ernie Muhly

Mushrooms are a nutritious native food that can be gathered in the wild or cultured. People commonly make a vernacular distinction between "mushrooms," which are edible, and "toadstools" which are poisonous. However, from a biological standpoint there is no distinction. Mushrooms are the fruiting-bodies (reproductive bodies) of fungi formed to produce and distribute spores.
These fruiting-bodies are similar to, but not exactly the same as rose buds, apples, and other fruits that produce seeds. The bulk of a fungus consists of almost invisible threads called mycelium, which run through the soil, wood or other substrate on or in which fungi feed and grow. The mycelium (also called the spawn) consist of a mass of even finer thread-like structures called hyphae, through which nutrients and water are obtained from the surrounding environment.
There are believed to be more varieties of mushrooms native to the Southeastern United States than to any other region of comparable size in North America. While the precise number of native varieties is not known, it is thought that between 3,000 to 5,000 different kinds of mushrooms can be found in the South. Most edible species are short-lived, lasting only a few days, so knowledge of native varieties relies heavily on local foraging traditions.
It is typically easy to tell edible mushrooms from poisonous ones. However, since some poisonous species grow among edible species, caution should be used when gathering mushrooms in the wild. Fortunately, of the thousands of varieties of mushrooms that exist there are only about 5 or 6 that are deadly poisonous. Distinguishing edible mushrooms from inedible (non-poisonous) ones can be more difficult. With a little training and care, though, most anyone can do it.
The life of fungi varies considerably. Some last for only one or two years, while others last for several years. However, the mycelia of mycorrhizal fungi which live in symbiosis with the roots of green plants, will usually live as long as the host plant. Certain species of mushroom producing fungi are associated with particular kinds of trees and plants. In fact, mushroom hunters looking for a certain type of mushroom will commonly seek out associated trees or forest types as good hunting locations. For example, Boletus variipes and the Chantarelle (Cantharellus cibarius) are usually found in mossy, sloping hardwood forests, especially those with oaks and pines. The Thick-footed Morel ( Morchella crassipes) can typically be found in rich hardwood forests, especially in flood plains. In pine forests in late autumn the Short-stemmed Bolete(Suillus brevipes) often appears. Field mushrooms, also called Champignons(Agaricus campestris) and Fairy-ring mushrooms, or Scotch Bonnets (Marasmius oreades), can often be found growing in fertilized meadows and pastures.

1. Gathering Mushrooms

The best way to learn about gathering and harvesting mushrooms is to join a local mushroom group, go on their outings and learn from experienced collectors. If there is not a local group you can join, try to find someone who knows about mushrooms to teach you. Pocket field guides and other books can be helpful but are generally a poor substitute for the knowledge and experience you can gain from an apprenticeship. Collecting mushrooms in the wild requires very little equipment: a knife or trowel for detaching mushrooms from their substrate; waxed paper (or small paper bags) in which to wrap the mushrooms, and an open basket for carrying the collection. Each specimen should be carefully collected, being sure to include the base of the stalk. To protect the mushrooms, they should be inserted lengthwise into a cylinder made by rolling up some wax paper. When full, the ends of the wax paper cylinder should be twisted to prevent the mushrooms from falling out. Plastic wrap and plastic bags should not be used. Plastic retains moisture too well and allows heat to build up which can cause the mushrooms to stew in their own juice.
It is important to keep mushrooms clean while collecting. It is easier to pick and keep mushrooms clean than it is to clean them later. When collecting in the wild, you should never harvest more than you can use. It is also important to avoid damaging the habitat since fungus mycelium needs to remain undisturbed in order to continue producing mushrooms. Picking mushrooms should not endanger the fungus.
The number of mushrooms that can be sustainably harvested from the wild depends upon the "carrying capacity" of the environment. Unfortunately, there is currently no reliable way of accurately determine carrying capacity. Thus, if large quantities of wild mushrooms are picked for sale or other purposes, an area can be unknowingly over-harvested, making it unable to continue producing wild mushrooms. While it may be possible to assist native species grow in the wild, not enough is presently known about the process to make such attempts advisable.
Mushroom culturing and harvesting can be undertaken to yield gourmet mushrooms, short-lived mushrooms (such as the shaggy mane which may only last for 2-days), and other types of mushrooms that are too expensive to buy for home use. Mushroom culturing can also provide a good economic return as an additional (alternative) crop on a family farm. However, to be successful in whatever level of mushroom cultivation you choose, it is important to conduct a realistic evaluation of time and resources available for the endeavor. If you manage to acquire or produce a significant quantity of mushrooms, it may be necessary to preserve those which cannot be consumed or sold. Mushrooms can be preserved by drying, canning or freezing. Freeze drying is generally the best way to preserve mushrooms, though it is also the most expensive. For frying, stuffing and baking, fresh mushrooms work best. Mushrooms that have been dried work well in soups and other dishes.
Nutritionally, fresh mushrooms contain around 8% fat as a percentage of calories; 25% folic acid in micrograms (ug)/100g; 38% protein as a percentage of calories, and usually contain 8 or 9 amino acids. They also can provide 0.46 milligrams Riboflavin (Vitamin B2)/100g; 2.2 milligrams Pantothenic Acid (Vitamin B5)/100g; and 16 micrograms Biotin/100g. Mushrooms when raw are approximately 90% water, and when dried their water content is about 15%. Depending on the species, they may also contain carbohydrates, fiber, calcium, phosphorus, iron, sodium, potassium, Thiamine, Niacin, and occasionally Vitamin C, and on the whole are a fairly nutritious food.
In A Field Guide to Southern Mushrooms, by N.S. Weber and A.H. Smith, the following edible species of mushrooms are recommended for beginning collectors: Agaricus campestris -- Field Mushrooms, Pink Bottom (Basidiomycetes), can be found in meadows, lawns and pastures, often abundant and forming fairy rings or arcs from spring to fall.
Agaricus porphyrocephalus (Basidiomycetes), are found late in the fall in lawns and mowed areas.
Agaricus solidipes (Basidiomycetes), can be found from late spring through the summer scattered in grassy areas and lawns.
   Boletus griseus (Basidiomycetes), can be found during the summer and fall as widely distributed and sometimes abundant specimens that are generally associated with oaks and open oak woods.
Boletus pinophilus (Basidiomycetes), can be found during the summer, scattered to gregarious under pines in the coastal plain.
Boletus variipes (Basidiomycetes), is widely distributed typically under hardwoods, and occasionally with pine, and found during the late spring into fall. Bovistella radicata (Gasteromycetes), is also widely distributed, and found on thin sandy soil, in open places and on cultivated and disturbed ground during the summer and fall.
Calvatia cyathiformis (Gasteromycetes), is widely distributed in meadows, grassy areas, lawns, and open woods during the summer and fall.
Cantharellus cibarius -- Chanterelle "MDNM" (Gasteromycetes), is usually found in groups in mixed woods, especially oak and pine.
Cantharellus cinnabarinus -- Cinnabar Chanterelle "MDNM" (Gasteromycetes), is often found in large drifts on mossy banks of streams and paths in mixed woods.
Craterellus fallax -- Black Trumpet Chanterelle "MDNM"    (Gasteromycetes) is found during the summer and fall, widely distributed and often abundant, scattered or in arcs on the ground in deciduous and mixed woods, and is common and often in large numbers on damp, mossy banks in those woods.
Flammulina velutipes -- Velvet Foot "MDNM" (Basidiomycetes), is found during the late fall to early spring during wet cool weather, and is widely distributed in dense clusters on logs, stumps and standing dead trees, especially elms, aspen and willow.
Hericium erinaceus -- Hedgehog Mushroom, Lion's Mane "MDNM" (Gasteromycetes), is usually solitary, arising from trees, stumps, and logs of broad-leaved trees, particularly oak, beech, maple and sycamore during the summer and fall and into early winter.
Hydnum repandum (Gasteromycetes), are often found in large numbers in leaf-litter under mixed trees especially where oak and/or blueberries occur during the summer and fall.
Lactarius corrugis (Basidiomycetes), is found during hot wet weather in the summer and early fall, scattered to gregarious in deciduous and pine-oak woods and in shaded lawns with oaks.
Lactarius hygrophoroides (Basidiomycetes), is widely distributed in deciduous or mixed woods from late spring to early fall.
Lactarius indigo -- Blue Lactarious®MDNM¯ (Basidiomycetes), is found during the summer and fall, or early winter, scattered to gregarious in mixed woods, especially under or near oaks.
Lactarius paradoxus (Basidiomycetes), is solitary to gregarious and found under 2- and 3-needle pines in late summer to early winter, and is often abundant and conspicuous in shaded lawns in late fall
Lactarius volemus (Basidiomycetes), is found during hot wet weather in the summer and early fall, scattered to gregarious in deciduous and pine-oak woods and in shaded lawns with oaks.
Laetiporus sulphureus -- Sulfur Shelf, Chicken Mushroom "MDNM" (Gasteromycetes), grows on dead or dying trees, both deciduous and conifers, but especially oak and willow. It can form huge clusters weighing many pounds, and is found from summer to early winter.
Morchella crassipes -- Thick-footed Morel "MDNM" (Ascomycetes), is found in early spring, sometimes around dead elms, under old apple trees, and in rich hardwood forests, but especially in floodplains.
Morchella elata -- Black Morel "MDNM" (Ascomycetes), is found during the spring near conifers, ash and apple trees, and also in mixed woods, or possibly under hardwoods.
Pleurotus ostreatus -- Oyster Caps, Oyster Mushroom "MDNM" -- (Basidiomycetes), are widely distributed and common, and can be found clustered, scattered, or in shelving masses on a variety of hardwoods, both living and dead from the fall on into the spring.
Suillus brevipes -- Short-stemmed Bolete "MDNM" (Basidiomycetes), are found from the late fall through the winter, and are scattered to gregarious under pines, especially 2- and 3-needle pines.
Suillus decipiens (Basidiomycetes), are found in dry pine woods and pine-oak woods from the summer into winter.
Suillus pictus (Basidiomycetes), are found during the summer and fall, and are associated with eastern white pine and common only in the mountains.
Volvariella bombycina -- (Basidiomycetes), are found in the summer and fall during hot weather, and are solitary to gregarious, often growing from wounds on living trees as well as on dead trees and logs of hardwoods, particularly elm, maple, magnolia, beech and water tupelo.
Volvariella volvacea -- Straw Mushroom, Patty Straw "MDNM" (Basidiomycetes), are found during warm to hot wet weather, and are quite gregarious on piles of decaying vegetable matter such as stable sweepings, piles of leaves, and compost heaps.

2. Culturing Mushrooms

The majority of mushrooms which have been cultured with the greatest success are those whose growing conditions fit narrowly defined parameters. Shiitake mushrooms, a Japanese import belonging to a family of "wood-destroying" fungi are in vogue, in part because they grow well on freshly cut oak logs. "Shitake" literally means "oak mushrooms," though they can be cultured on sweet gum and red maple. Tops of recently cut oaks that are left after wood harvest may be cut into small logs about 3 feet in length and inoculated with the spores. The Shiitake mushroom's mycelium is a primary decomposer. After two years of growth, Oyster mushrooms, which are secondary type decomposers, can be cultivated quite nicely on the same logs. The button-type or Agaricus mushrooms thrive on horse manure and other bedding materials and also do well in caves.
The type of mushroom one chooses to cultivate depends largely on the type of growing material that is available. Mushrooms cultivated indoors usually require large amounts of water and strict climate control. This makes large-scale indoor culturing expensive and perhaps an environmentally inappropriate undertaking. Culturing mushrooms also requires the acquisition of spawn which is introduced into the growing medium. Most small-scale mushroom growers choose to purchase spawn rather than produce their own.
To produce spawn requires that the desired fungi be isolated in order to make a standard inoculum. The substrate on which to produce the spawn is then selected, which at this point is the mycelium growing on a prepared medium. Once the spawn is produced, the growing medium is inoculated. Then there is nothing left to do but wait to see if the process was successful. Establishing a commercial mushroom operation can be very expensive and somewhat risky. Anyone considering mushroom farming should be sure they can afford the venture.
The number of mushrooms available for culturing and in markets is limited because of the complexity of operation and limited success associated with mushroom culturing. However, there are a number of native and other mushrooms worth considering as possible edible species for culturing in the U.S., such as:

Agaricus campestris -- Field Mushrooms, Pink Bottom "MDNM" -- (Basidiomycetes, native)
Agaricus porphyrocephalus -- (Basidiomycetes, native)
Agaricus solidipes -- (Basidiomycetes, native)
Coprinus comatus -- Shaggy Mane "MDNM" -- (Basidiomycetes, native)
Flammulina velutipes -- Velvet Foot "MDNM" -- (Basidiomycetes, native)
Ganoderma lucidum -- Reishi "MDNM" (Oriental, medicinal);
Grifola frondosa -- Hen of the Woods, Maitake -- (Basidiomycetes, native); see also Polyporus frondosus and Meripilus giganteus (Giant Polypore)
| Hericium erinaceus -- Hedgehog Mushroom, Lion's Mane -- (Gasteromycetes, native)
Laetiporus sulphureus -- Sulfur Shelf, Chicken Mushroom, Chicken of the Woods -- (Gasteromycetes, native)
Pleurotus ostreatus -- Oyster Caps, Oyster Mushroom -- (Basidiomycetes, native)
Stropharia rugoso-annulata -- King Stropharia (Basidiomycetes, native); see also S. melanosperma
Volvariella volvacea -- Straw Mushroom, Patty Straw -- (Basidiomycetes, native)

Before getting into the mushroom business it is important to do adequate planning and market research. You need to determine if there is a large enough market for your product and whether the market price will provide a sufficient return to make your venture profitable. You should also consider whether the mushroom operation you are planning is consistent with your other goals and whether you have the resources needed to be successful. A resource evaluation should consider: land, soils, water, buildings, equipment, skills, labor and management time, sources of information, assistance and credit, input supplies, processors and a distribution network. Also of concern is whether you can afford to get into a new enterprise that may take up to several years to become profitable!
According to "Shiitake Mushrooms: An Alternative Enterprise Guidebook," published by The Harlem Valley Planning Partnership, Dutchess County, New York (1991), a 200-log Shiitake farm is not a profitable undertaking. The Partnership reported that a 3000-log Shiitake operation employing a Controlled Environment Chamber could become profitable in about 3-years, but it would require an initial investment of $85,700.
Nereide G. Ellis, a consulting mycologist in Arlington, Virginia who grows mushrooms for sale, estimates that a 1000-log Shiitake operation would cost between $1400 to $1800 the first year if the logs were free and all equipment and supplies were purchased new. While there would be no profit the first year, in the second year one could expect a $2000 to $3000 profit, and in the third, a $1000 to $2000 profit. If a new set of 1000 logs were begun each year, the major cost would be the purchase of spawn ($400 for paste, $750 for plugs), labor, and miscellaneous supplies, and the production would be continuous.
The above costs do not take into account marketing and transportation expenses, but these costs could be minimized by coordinating with a vegetable wholesaler or by participating in an urban farmers market where prices might be higher and the demand greater. According to Nereide Ellis, mushrooms grown outdoors lend themselves well to organic production, which could fill a niche that might yield additional profits. Spent logs are also a good source of garden compost material which could help off-set farm expenses or be sold.

3. Fungal and Mushroom Growing Conditions

The distribution of fungi throughout the world is closely related to the distribution of green plants. Fungi, in combination with bacteria, play an active part in the natural decomposition of organic matter. In addition, soil fungi store carbon dioxide and cause various chemical reactions, and water fungi help purify polluted waters.
Fungi grow in many diverse environments. All species of fungi require ground water and moisture. Since fungi feed on the decomposition of organic matter, a source of organic material is also required. Different fungi grow on organic matter in different stages of decay. Thus, the species that can be found in a certain location depends greatly upon the type of decomposing matter available, and its current state of decomposition.
Since different species of fungi and their fruiting bodies are associated with certain plants, soil porosity, soil type and pH, as well as nutrient availability also help determine the species of fungus growing in a location. Mushrooms act like sponges, holding water for the forest. If the forest cover, sod or diverse biological associations in which they are living is altered, then their ability to reproduce and survive is jeopardized. Like most symbiotic relationships, the balance between a favorable environment and one in which species disappear is not well understood. Since mushrooms make micro-nutrients available as food for the trees and other plants with which they coexist, and since those trees and other plants provide nutrients for the fungi, acid rain and the changes that occur in ecosystems because of the acidity, seem to create problems for the fungi. In the top four to eight inches of the forest floor, acid rain adversely affects the natural pH of the environment, which in turn adversely affects the fungi's ability to convert nutrients into useful forms.
Radically changing an ecosystem, as is done with clearcutting and so many other financially driven environmental policies, also adversely affect the survival of fungi and their fruiting bodies. Fungal ecology, as concerns the majority of species, has more to do with sustainable land use practices, than it does with currently fashionable agricultural and forest methodologies. A majority of species of fungi, including many good edible ones, have not been successfully cultivated, because it is not feasible to re-create their growing conditions in isolation from their normal environment.
Literature on Mushrooms
Aurora, David. Mushrooms Demystified. Berkeley, CA: Ten Speed Press, 1979.
Chang, S.T. and W.A. Hayes. The Biology and Cultivation of Edible Mushrooms.
New York: Academic Press, 1978.
Chang, S.T. and P.G. Miles. Edible Mushrooms and Their Cultivation. Boca Raton, FL: CRC Press, 1989.
Harris, B. Growing Wild Mushrooms. Berkeley, CA: Wingbow Press, 1976.
Kibby, Geoffrey. An Illustrated Guide to Mushrooms and Other Fungi of North America. Stamford, CT: Longmeadow Press, 1993.
Miller, Hope. Hope's Mushroom Cookbook. Eureka, CA: Mad River Press, 1993.
Oei, Peter. Manual on Mushroom Cultivation. Sarphatistraat 650, 1018 AV Amsterdam, The Netherlands: Tool Publications, 1991.
Phillips, Rodger. Mushrooms of North America. New York: Little, Brown and Co., 1991.
Royse, D.J. and L.C. Schisler. "Mushrooms: Their Consumption, Production and Culture Development." Interdiscip. Sci. Rev., 5 (1980): 324-332. Smith, A.H. and N.S. Weber. Mushroom Hunters Field Guide. Ann Arbor: University of Michigan Press, 1980.
Stamets, P. and J.S. Chilton. The Mushroom Cultivator. Olympia, WA: Agarikon Press, 1983.
Weber, N.S. and A.H. Smith. A Field Guide to Southern Mushrooms. Ann Arbor: The University of Michigan Press, 1985.
Consultants, Information and Supplies

The North American Mycological Association 3556 Oakwoood Ann Arbor, Michigan 48104-5312 (313) 971-2552
   Nereide G. Ellis Consulting Mycologist Alternative Specialty Crops 3898 North 30th Street Arlington, Virginia 22207 (703) 243-0380
   Fungi Perfecti. Post Office Box 7634 Olympia, Washington 98507 (800) 780-9126
   Hardscrabble Enterprises, Inc. HC-71, Box 42 Circleville, West Virginia 26804 (304) 358-2921
   MushroomPeople Post Office Box 220 Summerton, Tennessee 38483 (615) 964-2200
   Walnut Meadows Route 3, Box 186 Bruceton Mills, West Virginia 26525 (304) 379-3596