Mushrooms in the Mississippi Delta and beyond: Winter and early spring
This article was originally published by Delta Wildlife in the Winter 2020 issue of Delta Wildlife Magazine (PDF).
A stroll into woodlands in the Mississippi Delta and beyond frequently reveals rich, diverse habitats of natural mixed-hardwood forests. This article focuses on mushroom species that produce flushes of abundant fruiting bodies during winter, which is usually the wettest season in the Delta. Mushrooms may form rapidly after a rain, but the fruiting bodies of most fleshy species tend to disintegrate within hours or days after forming. Early visits to forests soon after a rain usually provide the best views of mushroom blooms.
Mushrooms belong to the microorganism group, fungi, and are in their own kingdom due to their unique structural characteristics and means of obtaining energy. Fungi use specialized enzymes to obtain food and energy from organic matter of other organisms. Most species are too small to be seen with the naked eye. However, some form large masses of tissue known as mycelium. These macrofungi form fruiting bodies of various sizes and shapes, growth forms and developmental types.
Common names include agarics, boletes, chanterelles, earthstars, morels, polypores, puffballs, stinkhorns, truffles and trumpets. Other groups are called bird’s nest, coral, cup, gill, jelly, pore and tooth fungi. Macrofungi are further categorized by how they obtain energy and nutrients as mycorrhizal, decomposers, parasites or pathogens.
Most larger, fleshy mushrooms growing on forest soils are mycorrhizal. These fungi form a symbiotic relationship, obtaining carbohydrates from tree roots, and in return, providing increased adsorption of soil nutrients and physical protection. Decomposers obtain energy by the decay of wood and other plant debris. Parasitic-type mushrooms derive food and energy from living plant tissues, and true parasitic species induce diseases in living trees by attacking and sometimes killing only parts (individual limbs or roots) or the entire tree.
A winter-blooming mycorrhizal mushroom is the light grayish to brown-colored shrimp of the woods (Entoloma arbortivum). This mushroom has pink or gray gills that run down the stalk beneath the cap. The gills release salmon to pink spores to the ground surface. This species can be found alone or with – possibly parasitizing – honey mushrooms (Armillaria species) near roots of decaying hardwoods such as oak, maple, and beech. It is considered edible, but other related Entoloma species are poisonous.
Brown deer truffle (Elaphomyces granulatus) is common in the U.S. and Europe. Truffles form underground in association with tree roots in lowland and riparian stands of beech and red oaks. Deer can smell the fruiting bodies and may be seen scratching the ground with their hooves to expose and feed on them. Deer truffles are unpalatable to humans, unlike the highly sought European truffles. Many wildlife species and insects eat wild mushrooms as they become available during moist periods.
Parasites and pathogens
Parasites and pathogens are the second group of macrofungi. This group includes the hedgehog fungus (Hericium erinaceus), also known as the bear's head, lion’s mane, or bearded tooth fungus, which form white, soft and spongy fruiting bodies (conks) with distinctive downward-pointing spines (teeth) that turn brown with age. These develop from tree wounds or fallen logs, especially on oaks, maples, sugarberry, and beech damaged by fire or logging. The fungus causes white wood decay in the heartwood of the lower trunk. It is edible when young, but sours with age. Certain chemicals from this fungus have potential uses in medicine for human nerve regeneration.
The golden-yellow to bright orange fruiting bodies of the white-pored chicken of the woods (Laetiporus cincinnatus) fungus occurs almost exclusively on oak trees. It causes decay of tree roots, and fruiting bodies develop on or near the base of the tree at ground level, usually in clusters, with furrowed surfaces, cream to white margins, and a pore surface instead of gills under the cap. This species is usually edible when young, but may cause gastrointestinal issues in some people.
The related chicken of the woods (Laetiporus sulphureus), another edible species, forms larger, overlapping clusters of fan or bracket-shaped fruiting bodies with wavy yellow margins in the spring until fall. It causes a brown cubical butt-rot of wood in living trees, particularly oaks, but occasionally on conifers. Bacterial contamination renders older fruiting bodies often inedible or somewhat poisonous.
The familiar hen of the woods (Grifola frondosa), known locally as sheep's head or maitake, is an edible species forming near the base of healthy oak trees, often repeatedly for many years. It produces compound clusters of brown to grayish fan-shaped fruiting bodies with white pore surfaces under caps on short, thick, white stalks. Fresh collections are best for consumption, but dried fruiting bodies may be ground for tea. It has anti-viral, anti-tumor properties and the ability to normalize glucose levels in diabetics.
The third group of macrofungi serve as natural nutrient recyclers. The oyster mushroom (Pleurotus ostreatus) is a showy white to cream-colored fleshy mushroom with a convex white cap, cream to yellow radiating gills beneath the cap, and very short white or absent stalk. The fruiting bodies may be solitary or form overlapping clusters on dead trees, logs, or stumps of broadleaf trees, especially oaks and willows. Young fleshy parts are edible and rich in B vitamins, except B-12. Medicinal uses include tumor-inhibiting and blood cholesterol-lowering properties and antiviral proteins for the treatment of HIV. This species also provides environmental benefits by breaking down petroleum-based pollutants and adsorbing toxic heavy metals from soils.
The turkey tail fungus (Trametes versicolor) forms thin, fan-shaped fruiting bodies with caps of multi-colored (orange to blue) concentric rings on fallen broadleaf tree limbs and logs. Among the most studied medicinal fungi, it is included in a protein-bound polysaccharide drug that helps control the spread of human cancer.
Another group of decomposers are transparent, have a gelatinous to rubbery texture and are flexible to the touch. Witches' butter (Tremella mesenterica) forms brilliant, yellow-translucent fruiting bodies on dead hardwoods, especially oaks. They are edible, but relatively tasteless. The wood ear fungi (Auricularia auricula-judae and A. angiospermarum) are edible mild-flavored species used in Chinese cooking. They appear as light brown flexible ears often in cup-like clusters on a woody substrate.
The amber jelly fungus (Exidia recisa) develops spherical cinnamon-brown fruiting bodies that frequently occur on small dead tree branches.
Morels (Morchella species) are highly-prized edible fungi formed on the ground during winter and spring, producing erect fruiting bodies often with a thick white stalk and a pitted and ridged cap that resembles a sponge. The sponge-like surface appears as clusters of small cups with ridges between them. True morels are among the most delectable of all fungi. Some related fungi such as the bell morels (Verpa species) are edible and flavorful as well. Others, however, are not. For example, mushrooms in the Gyromitra genus produce varying amounts of gyromitrin, a water-soluble carcinogenic toxin. False morels (Gyromitra esculenta) as well as the saddle fungi (Helvella species) can be quite poisonous.
Editor’s note: This article is the second of four in a seasonally themed series by Dan Wilson. Although written originally for mushrooms in the Mississippi Delta, most of these mushroom species are also found across the Southeast and beyond.
For more information, email Dan Wilson at email@example.com.
Research Plant Pathologist