Genus at a glance
Field | Detail |
|---|---|
Classification | Species (Psilocybe cubensis) |
Family | Hymenogastraceae |
Described species | Over 100 in the Psilocybe genus; B+ is a premier domesticated cultivar of cubensis. |
Spore print | Dark purplish-brown to blackish |
Distribution | Anthropogenic and subtropical pastures worldwide |
Habitat | Enriched dung, leached soils, humic grasslands, and indoor grain substrates |
Key alkaloids | Psilocybin, psilocin, baeocystin, norpsilocin |
Overview
B+ is the strain most people meet first. For decades it has been the default entry point into cultivation, the one passed hand to hand through the spore trade because it colonizes aggressively, fruits heavily, and forgives the kind of mistakes a beginner makes. Other strains sulk. B+ mostly just grows.
That reputation is the real story here, and it is earned. Whatever else is true or unproven about B+, its standing as a forgiving, high-yielding workhorse is the thing that made it a fixture. It is the working-class hero of the spore underground, and it got there on vigor rather than mystique.
Lineage and creation myth
Psilocybe cubensis itself is well documented. It was formally cataloged in the early 20th century and has since been mapped across subtropical regions worldwide. B+ is a much later development, a cultivar stabilized through underground selection in the last few decades rather than a wild population with its own scientific record.
Here is where the legend starts, and it is worth telling before we test it. The story the community has carried for years names a breeder called "Mr. G," who supposedly developed B+ in Florida sometime in the late 1980s or early 1990s. The account holds that he crossed strains into a hybrid tough enough to shrug off temperature swings and throw unusually large fruit. It is a good origin story, and it is the one you will find repeated across most vendor pages nearly word for word.
Now the record. Nobody has documented who actually first isolated B+. The history is a blur of traded spore prints, hand-written labels, and mail-order catalogs, with no paper trail leading back to a named originator. The "Mr. G" attribution is oral history, not a verified account. The specific claim that B+ is a deliberate hybrid is the shakiest part, because cubensis genetics do not bend to amateur crossing the way the story implies, and later genetic work on cubensis strains has found far less distinctness between named varieties than the marketing suggests. What is solid is the vigor. The lineage really does colonize fast and fruit big. What is folklore is the man, the place, the date, and the hybrid. The mushroom is real. The biography is a campfire story.
Phenotype and grow behavior
B+ is known in maturity mostly by size and by how agreeable it is to grow. The cap starts chestnut brown, smooth and slightly shiny when wet, and opens into a broad umbrella that can exceed ten centimeters across, fading to a warm gold as it ages. The stem is thick, white, and fibrous. Bruise it and it stains blue, the ordinary oxidation reaction of any active cubensis rather than anything specific to this strain.
Its grow reputation is the whole reason it spread. Growers describe it as fast to colonize, heavy-fruiting, and unusually tolerant of the conditions that stall pickier strains. Note the register there: this is what cultivators report, not a controlled measurement. The forgiving reputation is real as reputation. The "survives anything" framing is where folklore takes over from fact.
Potency: reputation versus data
Potency is where you should keep a hand on your wallet, because this is where reputation and data pull in different directions and both get quoted as fact.
The reputation splits. Some sources call B+ a baseline, average-strength strain. Others, usually the ones selling it, call it above average. Here is the honest problem with both: there is no rigorous, strain-specific potency dataset for B+. The numbers you see quoted with a decimal point almost always trace back to a vendor listing, not a lab. What we do have is context. The old cubensis reference figure is about 0.63 percent psilocybin by dry weight, from Stamets in 1996, still used as the baseline that later testing grades against, including in Hyphae Labs' open potency work. And the measured spread among cubensis cultivars is wide enough that the same strain, grown by the same cultivator, tests differently from one flush to the next.
That spread is the actual lesson. The people who run the testing, and the genetic researchers who have looked hardest at cubensis, land on the same conclusion: how a mushroom is grown, harvested, and dried moves its potency more than which strain it is. The ongoing Hyphae Psilocybin, which tests submitted cubensis grows, keeps showing the same scatter. So when someone quotes you a confident B+ potency number, the useful response is to ask where it was measured, by whom, and on which grow. Usually there is no answer. Treat any single potency number for B+ as one data point from one grow, not a property of the strain. Hold the number loosely, because the people who generate the numbers do.
A closing quirk
The name is the quirk. "B+" sounds like a grade or a lab designation, something measured and assigned. It is neither. It is a marketing label from the early spore trade meant to suggest "big" and "plus," a bit of underground branding that stuck so hard it now reads as taxonomy. A strain famous for being the honest, unpretentious beginner's mushroom carries a name that is pure salesmanship, and almost nobody notices.
