Over the last several decades (beginning in the late 1950’s with the LIFE Magazine publication “seeking the magic mushroom”) Psilocybin-containing-mushrooms have both risen and fallen in popularity, an ebb-and-flow which coincidentally mirrors the amount of studies/research/clinical trials going on at a given moment, and legal policy. In the present day both the number of clinical trials ongoing, and the number of individuals who are interested in magic mushrooms is at an all-time-high, however despite this surge in popularity most people know very little about the differences in growing characteristics and effects between different species and strains of Psilocybe Mushroom.
There are over 200 species of mushroom in the Psilocybe genus, with each possessing significant differences in potency, visual appearance, & growing requirements. By far the most well-researched, commonly-found, and easy-to-cultivate species is Psilocybe Cubensis, and this has led to the identification of several hundred “subspecies” within the ‘Cubensis’ species. These subspecies are commonly referred to as “strains” by those in the mushroom world, however from a microbiology and taxonomy perspective this terminology is not entirely accurate.
Although these strains are all members of the Psilocybe Cubensis species, they can also (just like species) differ significantly in both physical characteristics and in the concentration of psychotropic compounds that are present in fruiting bodies OR mycelium (some strains contain much higher amounts of active compounds in the mycelial stage). Cubensis strains (despite all being the same species) can also differ quite drastically in growing characteristics, for example; how resistant they are to contamination, colonization speed, and overall yield - although these factors are also influenced significantly by how much an individual culture has been isolated and thus how strong the genetics of that individual culture are (more on that in a bit).
Different Psilocybe Cubensis “Strains”
The reason why different varieties of the Psilocybe Cubensis species are currently referred to as “strains” is likely attributable to the influence that the already established cannabis industry has over the emerging mushroom industry. Over the last 2 decades, the stigma surrounding cannabis has evaporated, resulting in an explosion of cannabis production & consumption across North America. This demand has catalyzed the creation of several thousand cannabis strains, from “Northern Lights” to “Girl Scout Cookies” to “Blue Dream.” Since Psilocybe mushroom farmers are in a relatively similar realm to cannabis, and many have transitioned from the cannabis industry, this is likely why the fondness for categorizing by “strain” has seeped into the mushroom world.
Both Cannabis and Psychedelics share many parallels, like the demographic of individuals who consume them, the fact that they both offer effective treatment of several debilitating conditions, and the fact that both can be (relatively) easily grown in your own home, however from a biology/taxonomy standpoint they are quite different! While different cannabis strains can be “mapped” through genetic sequencing, and their lineage traced back to the original “parents” (because genetic profile does not change from generation to generation), the same cannot be said for most Psilocybe Cubensis mushrooms (because of the reproductive process fungi have evolved). To fully understand why “varieties” is a more apt term, you must first understand this reproduction process (which interestingly is closer to human reproduction than plant reproduction).
In nature, fungi reproduce by releasing millions of spores into their environment. Each time a single spore meets with another spore and “germinates” (the equivalent of mushroom-sex), a unique variety of mushroom is created that has similar genetics to its parents, but not identical. This is similar to how when two humans mate, their offspring tends to look like the parents, however is genetically unique. Therefore, every time you grow mushrooms from a spore print or spore syringe you actually create a brand new “strain” (from a strict taxonomy perspective). For example, let’s say there are two mycologists who are both researching “Golden Teacher” Psilocybe cubensis mushrooms. Both Mycologists inoculate an agar petri dish with a Golden Teacher Spore syringe, but now each have a different strain of Psilocybe Cubensis Golden Teacher that would show a different genetic profile if subjected to genetic sequencing. Hence the term strain is not accurate (as in order to be termed a “strain” genetic profile must be consistent from generation to generation). This is why the term “varieties” is a more apt description, as you could accurately state that both Mycologists started with a Golden Teacher variety, and now each have a new, different Golden Teacher variety.
Photo illustrating the differences between two different growers “Golden Teachers”
The only way in which the term “strain” can be somewhat-accurately used when cultivating mushrooms is if the mushroom culture is propagated via tissue cloning, which propagates the same genetic code from the tissue sample to a new growing medium. Although the term strain is more accurate in this context, the most accurate term would be isolation, since only some of the genetics present in the culture are being propagated (the genetics present in the tissue sample). Isolation is a process that allows for the selective propagation of the strongest genetics in a mushroom culture, and can serve to “refine” a culture over time by selectively furthering only beneficial traits like large fruiting bodies, rhizomorphic mycelial strands, and resistance to contamination. By selecting the largest, thickest, and strongest strands of mycelial growth from the petri dishes, the mycologist is effectively picking the strongest genetics or “the cream of the crop” from each petri dish in hopes that the next generation that grows from that mycelium will be stronger and faster to colonize. Ideally, the mycologist would also fruit these genetics after every few generations of isolation to ensure that good fruiting characteristics are still present in the genetic profile.
To illustrate how isolation can improve the characteristics and consistency of a mushroom culture, let's go back to our Golden Teacher Example, where both Mycologists had inoculated an agar Petri dish with Golden Teacher genetics. The first mycologist performs three isolations of his original specimen, each time selecting the strongest portion of the petri dish and propagating those to a new dish, before introducing the resulting culture to fruiting conditions. Since he performed three isolations, his mushrooms will have more consistency, faster colonization time, and likely greater yield than if he did not isolate at all. The second mycologist in our example performs six isolations, and because the second mycologist performed more isolations, and therefore further strengthened the genetic profile with each isolation, it's likely that her mushroom mycelium will colonize the fruiting substrate faster, grow bigger mushrooms, have a more dense pinset, and be even more resistant to contamination than the first mycologists culture.
Photo illustrating the difference between un-isolated (left) and isolated (right) mycelium
To add an additional element of complexity, once you have isolated and stable genetics in mycelium form, these isolate cultures can be combined in the same fruiting tray, and where the two cultures “meet” mushrooms will grow that bear characteristics of both isolations. If you were to take tissue samples from these mushrooms and propagate those via tissue cloning, you would create a “Hybrid” of the two cultures (that must be propagated via tissue cloning to remain a true hybrid). In order to better understand the difference between isolations and hybrids, let’s use an analogy between fungi and humans (as fungi are closer related to humans than they are to plants).
One of the most common hybrid strains - Albino Penis Envy - a mix of Penis Envy and Albino A+
Psilocybe cubensis is a species of fungi just like how Homo sapiens is a species of mammal. While it would be quite difficult (and impossible under natural conditions) to mate a Psilocybe Cubensis mushroom with another Psilocybe species, such as Psilocybe Azurescens (equivalent to mating a human with a chimpanzee), it is possible to mate a Psilocybe cubensis variety (for example Golden Teacher) with another Psilocybe cubensis variety (for example Penis Envy) to produce a “hybrid” (which would be similar to a caucasian human mating with a hispanic human) through the process described above (combining 2 mycelial cultures in one fruiting container, then tissue cloning the mushrooms that display characteristics from both cultures).
In summary, while It might seem nitpicky or futile to argue that Psilocybe cubensis “strains” should be referred to as “varieties, isolations or hybrids”, using proper nomenclature (even if it is more confusing) will undoubtedly raise the standard for professionalism within the mushroom space, and also solidify the importance of genetic isolation when doing mycology.
In short, the most simple way to differentiate between Species, Varieties, Strains, and Hybrids is; Species are distinctly identifiable genetically, Varieties are all categorized within one species and genetically similar, but not identical, Strains are tissue isolations which have a genetic profile that remains the same over multiple generations (provided every new generation is propagated from a tissue sample), and Hybrids are mixes of two genetically consistent strains.
Jeff Lebowe - Spores Lab