Common Name: Turkey Tail, Yun zhi (China), Karawatake (Japan) – The concentric multicolored rings are similar in pattern and coloration to the feathers comprising the tail of the wild turkey (Meleagris gallopavo).
Scientific Name: Trametes versicolor – A trama is a fungal structure comprised of loosely woven hyphal tissue (i.e. consisting of bundles of individual hyphae, which are the filamentous growth extensions of the fungus) that makes up the sterile tissue at the center of the fruiting body cap that extends into the spore-bearing pores. The Greek word trama means the woof or weft of a fabric (from trahere – to pull) and refers here to the fabric-like weaving of the hyphae. In the Trametes fungi, the central trama is accentuated by radiating rings. Versicolor means multi-colored. Coriolus versicolor, Polyporus versicolor and Polystictus versicolor are alternative scientific names that have been used in the past and are found in some references.
Potpourri: The turkey tail is one of the most recognizable and certainly among the most aesthetic of all forest fungi. It has the delicate tan, brown and cinnamon concentric gradations that grace the tail feathers of its avian namesake. With a modicum of imagination, one can envision a massed flock of turkeys compressed onto the surface of its primary habitat: the fallen log of a dead deciduous, hard wood tree. The notoriety of the turkey tail is global, its unique appearance having attracted human interest for millennia, most notably in Asia, where it is prized as a medicine of substantial benefit. Turkey tail identification is not without challenge, as there are at least two fungi that are quite similar in appearance when viewed from the top, which would be the normal stance of the observer. The first is actually called the False Turkey Tail due to this resemblance. A member of the Stereaceae or Parchment Fungus Family, which are in general thin and leathery polypore fungi, False Turkey Tail or more properly Stereum ostrea is sometimes also known as Stereum versicolor in acknowledgement of its own multi-colored cap surface. The key identification feature that can be used to distinguish a Turkey Tail from a False Turkey Tail is the underside of the cap. The former has visible, though minute, pores on the bottom while the latter is smooth. The photo above shows the top of S. ostrea on the right and the smooth bottom on the left.
The other Turkey Tail doppelganger is one of the more unusual polypore fungi, the multi-colored gill polypore, Lenzites betulina. Fungi in the family Polyporaceae are commonly known as polypores, as they have many (poly) pores, which are actually the openings for the spore-bearing tubes that extend from the underside of the cap. The multi-colored gill polypore, as the common name suggests, has what appear to be gills on the underside of the cap (like the ubiquitous gilled mushroom). However, the gills are not the same as the true gills of a normal mushroom in that the spore bearing basidia are not connected directly to the sides of the gill surface. Rather the “gills” of L. betulina are in reality a radial arrangement of tubes and pores. Inspection reveals that the “gills” are very tough and leathery, like the polypore to which they adhere. The real Turkey Tail can thus be fairly easily identified in the field. One need only find a polypore with limbate, concentric rings and turn it over. If it has pores, it is a Turkey Tail.
And if it is a Turkey Tail, then you can eat it, though the tough hyphae woven trama is not likely to be palatable to the average mycophagist. Those who have tried it characterize the taste and texture, once satisfactorily moistened and masticated, as fungus flavored chewing gum, hardly a palatable experience to most. Assuming that someone was inclined not only to chew a Turkey Tail, but also to swallow and digest it, the experience, though not high cuisine, would be of significant nutritional value. P. Stamets in Mycelium Running provides that a 100 gram serving has 369 kilocalories (which we usually refer to as simply calories), 10.97 grams of protein, 77.96 grams of carbohydrates, 71.3 grams of dietary fiber, 8.7 milligrams of iron, and 570 milligrams of potassium. Though this nutritional content is not all that exceptional in comparison to many of the myriad other edible fungi, it is hard to believe that the scabrous turkey tail is that wholesome – you could make a tolerably salubrious breakfast meal out of it. However, it is much more likely that the casual wild food aficionado would gather the “tails” and make a ptisan (tea) of them, taking advantage of the well documented and scientifically established medicinal properties of Trametes versicolor.
The Turkey Tail (more correctly Yung zhi in China and Karawatake in Japan since most of the research is conducted in Asia) is likely the most well documented of all the fungi from the standpoint of medicinal applications. It has notable and measurable effects on tumorous carcinogenic growths with some organoleptic specificity. The trials have included in vitro (outside the body in an artificial environment), in vivo (live animal) and human clinical evaluations. The non-human trials have demonstrated that the chemical components extracted from the Turkey Tail have potential in adjuvant cancer therapy, which is to say that they enhance the effect of other drugs in shrinking tumors when taken in concert with the primary drug. This ameliorative effect is also referred to as a biological response modifier, or BRM; the additive component (in this case a derivative of the fungus) acts as a modulator of the immune system in improving the host body’s tumor response. As an example, a meta-analysis of eight separate controlled and randomized trials which included 8,009 patients that was conducted in Kyoto, Japan in 2007 revealed that the use of adjuvant therapy with extracts from Turkey Tail fungi “improves the survival of patients after curative gastric cancer resection.” Other trials have demonstrated similar statistically significant effects on prostate, esophageal, colorectal, breast and lung cancers.
The compounds that are extracted from Turkey Tail are polysaccharides, long carbohydrate molecules that break down when hydrolyzed into monosaccharides like glucose. Polysaccharide – Kureha, simplified to PSK, is the predominant fungal compound used for medicinal applications; it is sold commercially as Krestin. PSK has been an approved cancer drug in Japan since 1977 where annual sales are estimated at over half a billion dollars, about 25 percent of the total Japanese expenditure for cancer-related drugs. A second polysaccharide that has more recently been extracted from Turkey Tail is polysaccharide peptide, or PSP. It differs chemically from PSK in its constituent monosaccharides; PSK yields rhamnose and arbinose and PSP yields fucose. The more important functional difference, however, is in the modulating effect of PSP on the immune system. Trials have indicated potential as an agent against HIV replication. The enzymatic efficacy of T. versicolor also makes it a strong candidate for mycorestoration, the use of fungi to remove harmful materials from the environment. This has been demonstrated in numerous studies of a variety of contaminants including organophosphates and mercury. As Turkey Tail is a white rot fungus, which means that it can decompose both wood cellulose and lignin, it has great potential for other industrial processes, notably the bleaching of wood pulp.