⚖️ UK Legal Notice: This guide is written strictly for educational, taxonomic, and microscopy research purposes. Psilocybe cubensis spores do not contain psilocybin or psilocin and are legal to purchase in the UK for microscopy research. Growing fruiting mushrooms from spores is illegal under the Misuse of Drugs Act 1971. Always comply with UK law. See our 2026 UK Legal Guide for full details.
⚡ Quick Answer
B+ is a variant of Psilocybe cubensis, widely circulated among mycologists since the 1990s and considered one of the most reliable reference strains for research. The spores are 11–16 x 7–11 micrometres, dark purple-brown, with a smooth wall and a clearly visible germ pore. Its large caps and thick stems produce exceptionally dense spore deposits, giving researchers plenty of material to work with. This guide covers the genetics behind B+, how to prepare a proper slide, how it compares to other strains, and how to store your syringe correctly so it stays viable.1990sWhen B+ entered wide mycology circulation
11–16µmSpore length — medium-to-large for cubensis
400xMinimum magnification to see spores clearly
Very HighTypical spore deposit density
Jump to a section
1. Where It Came From
2. What the Spores Look Like
3. Why It's Popular for Research
4. Strain Comparisons
5. How to Prepare a Slide
6. Storage Guide
FAQ1. Where Did B+ Come From?
B+ is a cultivar of the species Psilocybe cubensis — the same species as Golden Teacher, Penis Envy, and every other named cubensis strain. Think of it the way you'd think of apple varieties: a Braeburn and a Gala are the same species of apple, just different cultivars with their own characteristics.B+ has been in wide circulation since at least the 1990s, and its exact origin is one of the more debated points among collectors. Its documented history and consistency have made it one of the most cross-referenced cubensis strains available, alongside Golden Teacher.Where Does the Name Come From?
Unlike Golden Teacher, whose name has an informal folk-etymology, "B+" is simply a label — likely originating from an early cultivator's naming shorthand. No confirmed backstory exists, but the name has stuck for over three decades because of the strain's reliability.The Science Behind the Classification
Psilocybe cubensis was first described in 1906 by Franklin Sumner Earle from specimens found in Cuba, later reclassified into the genus Psilocybe by Rolf Singer in 1948. B+ shares this same species classification with all other cubensis strains — the strain name distinguishes the cultivar, not a separate species.
ℹ️ Key Taxonomy Fact — B+, Golden Teacher, Penis Envy, Blue Meanies, and all other named cubensis strains are the same species, Psilocybe cubensis. Strain names are informal cultivar labels, not separate scientific classifications. All cubensis strains share the same species-level spore characteristics under the microscope.
2. What B+ Spores Look Like Under the Microscope
B+ spores share the core cubensis features — dark pigmentation, visible germ pore, subellipsoid shape — but the strain is particularly known for the sheer volume and consistency of spores it produces.Size
11–16 × 7–11µm
Medium-to-large for Psilocybe. Clearly visible at 400x. Best measured at 1000x oil immersion.
Shape
Ellipsoid
Slightly more uniform and rounded than Golden Teacher's subellipsoid shape. Very consistent within a sample.
Colour
Dark Purple-Brown
Rich, deep pigmentation with excellent contrast under standard brightfield illumination at 400x.
Wall
Smooth, 0.5–1.0µm
No warts or surface features. Standard thickness, clearly visible at 1000x oil immersion.
Germ Pore
1.3–1.8µm Broad
A visible thin-walled window at the tip of the spore, clear and well-defined at high magnification.
Deposit
Very Dense
B+ produces some of the heaviest spore deposits of any common cubensis strain — a real advantage for prep.
Let's Break Each Feature Down
Shape — Ellipsoid: B+ spores tend to be slightly more rounded and uniformly ellipsoid than the subellipsoid shape seen in Golden Teacher. In practice this is a subtle difference you'll mostly notice when comparing the two strains side by side.Size — 11–16 x 7–11 micrometres: This overlaps closely with Golden Teacher's range but trends marginally smaller at the top end. At 400x you'll see the general shape and colour clearly; 1000x oil immersion reveals the finer wall and germ pore detail.Deposit density: This is where B+ genuinely stands out. Because its large, flat caps release spores so freely, B+ syringes tend to carry noticeably more material than average — useful if you're doing a lot of slide preparation in one sitting.
✅ What to Look for First — At 400x, you'll spot dense clusters of dark oval spores almost immediately with B+. Focus first on getting a clean, well-lit field of view, then move to 1000x oil immersion to examine wall thickness and the germ pore.
3. Why Is B+ So Widely Used for Research?
B+'s popularity isn't accidental — there are concrete, practical reasons researchers reach for it as often as Golden Teacher.Very High Spore Yield
B+'s large, flat-opening caps release spores in abundance, meaning your syringe carries more material and each slide prep is more forgiving of small technique errors.Consistent, Uniform Shape
Spores within a B+ sample look remarkably similar to each other, which helps when you're learning to judge whether variation you see is real or a preparation artefact.Clear Structural Features
Pigmentation, germ pore, and wall structure are all easily observable at standard magnifications without special staining — a big help for building confidence early on.Extensively Documented
Decades of circulation mean B+ has extensive published reference material available, letting you check your own observations against established benchmarks.Strong Comparison Baseline
Once you know B+'s morphology, it becomes a useful reference point for spotting subtle differences in other strains you study afterwards.Forgiving for Beginners
Because there's so much material in a typical B+ syringe, minor prep mistakes — a bit too much liquid, a stray air bubble — rarely ruin an otherwise usable slide.4. How B+ Compares to Other UK Strains
All Psilocybe cubensis strains share species-level spore characteristics, but there are real, measurable differences at the cultivar level. Here's how B+ stacks up against four other popular UK microscopy strains.| Strain | Spore Size (µm) | Shape | Deposit Density | Difficulty | Best For |
|---|---|---|---|---|---|
| B+ | 11–16 × 7–11 | Ellipsoid, very uniform | Very High | Beginner | High-volume slide prep |
| Golden Teacher | 11–17 × 7–12 | Subellipsoid, very consistent | Very High | Beginner | Reference strain, first slides |
| Mazatapec | 11–16 × 7–11 | Subellipsoid, stable | High | Beginner | Historical taxonomy research |
| Blue Meanies | 10–14 × 6–10 | Ellipsoid, compact | Moderate | Intermediate | Pigmentation contrast studies |
| Penis Envy | 11–17 × 7–12 | Subellipsoid, thicker walls | Low — rare | Advanced | Genetic mutation study |
B+ vs Golden Teacher — What's the Difference?
These are the two most commonly compared beginner strains, and they're genuinely close. B+ spores trend slightly smaller and more uniformly ellipsoid, while Golden Teacher's range extends a little larger with a subellipsoid shape. The practical difference most researchers notice is deposit density — B+ syringes often carry the heaviest spore load of any common strain, so if you're doing back-to-back slide prep, B+ tends to go further. Many researchers keep both on hand and use them as a comparison pair.B+ vs Penis Envy — Opposite Ends of the Spectrum
Where B+ is defined by abundance and consistency, Penis Envy is defined by scarcity. A genetic mutation keeps PE's cap partially closed at maturity, drastically limiting spore release — the opposite of B+'s wide-opening, high-yield caps. If you're building research skills, B+ is where to start; Penis Envy is worth adding once your technique is solid.5. How to Prepare a B+ Slide
Because B+ syringes carry such a heavy spore load, they're genuinely one of the easiest strains to get a usable slide from on the first try.What You'll Need
- Compound microscope — 400x minimum, 1000x oil immersion preferred
- Glass slides (25×75mm)
- Coverslips (#1.5, 0.17mm thick)
- Immersion oil (Type B) for 1000x work
- Lens tissue and isopropyl alcohol for cleaning
- Your B+ spore syringe
- Notebook for recording observations
1
Clean your slide — Wipe a glass slide with lens tissue dampened with isopropyl alcohol and let it dry completely. Dust and fingerprints create distracting artefacts that can look like contamination.
2
Agitate the syringe — Roll it between your palms for about 10 seconds, then shake gently for another 5. B+'s high density means it redistributes evenly quite quickly compared to lower-yield strains.
3
Add one small drop — Uncap the needle and press out roughly 0.05ml onto the centre of the slide. Less is more — too much liquid causes the coverslip to float and the spores to drift.
4
Apply the coverslip at an angle — Hold at a 45-degree angle, letting one edge touch the liquid first, then lower it flat. This pushes air out to the sides and reduces bubbles.
5
Start at 100x — Get an overview of the whole slide at low magnification. With B+, you'll typically spot dense, usable clusters almost immediately.
6
Move to 400x for observation — This is the main working magnification for shape, colour, and overall sample assessment. Practice measuring spores here with a calibrated eyepiece micrometer.
7
Use oil immersion at 1000x for fine detail — Add a small drop of Type B immersion oil directly on the coverslip and lower the 100x oil objective. This reveals wall thickness and the germ pore clearly.
8
Record your observations — Note dimensions, shape, colour, and any distinguishing features. Measure at least 15–20 spores for a reliable average, and photograph where possible.
⚠️ One Thing to Remember — Always cap the needle immediately after use. Every time the syringe is opened to air, there's a risk of contamination entering, which can ruin future slide preparations.
6. How to Store Your B+ Spore Syringe
Standard storage rules apply here, and B+'s high spore density means it tends to hold up reliably over long periods when stored correctly.| Factor | What to Do | Why |
|---|---|---|
| Temperature | Store at 2–8°C (standard fridge) | Slows microbial activity without damaging spores |
| Freezing | Never freeze | Ice crystals permanently damage spore structure |
| Light | Keep in complete darkness | UV and ambient light degrade viability over time |
| Position | Store upright, needle cap on | Prevents spores settling against the plunger seal |
| Container | Sealed bag or opaque container in fridge | Protects against light and fridge odours |
| Shelf life | 12–18 months under ideal conditions | Wall structure and clumping degrade beyond this point |
✅ Before Each Use — Bring the syringe to room temperature first, then agitate for 10–15 seconds before opening. B+'s density means it redistributes quickly, so you won't need the longer agitation some lower-yield strains require.
Ready to Get Started?
Tripping Store's B+ spore syringes are prepared under sterile conditions in the UK, with verified genetics and exceptionally high spore density — giving you plenty of material for reliable, repeatable slide preparation.Frequently Asked Questions
QWhy is B+ so popular for microscopy?
Three main reasons. It produces an exceptionally dense spore deposit, so every syringe carries plenty of material to work with. Its spores are also highly uniform, which helps beginners focus on technique rather than second-guessing whether variation is real. And its key identification features — colour, germ pore, wall structure — are all clearly visible at standard magnifications without special equipment.
QHow big are B+ spores?
B+ spores measure 11–16 x 7–11 micrometres — medium-to-large for Psilocybe cubensis, and similar in range to Golden Teacher though trending slightly smaller at the upper end. They're clearly visible at 400x, with fine detail visible at 1000x oil immersion.
QIs B+ legal to buy in the UK?
Yes — for microscopy research purposes. Psilocybe cubensis spores don't contain psilocybin or psilocin, so they're legal to buy, own, and study for microscopy and taxonomic research in the UK. Cultivating fruiting mushrooms from spores is not legal. See our full 2026 UK Legal Guide.
QWhat magnification do I need to see B+ spores?
You can see B+ spores clearly at 400x magnification. For finer detail — wall thickness and the germ pore — you'll want 1000x oil immersion with Type B immersion oil on the coverslip.
QHow does B+ compare to Golden Teacher for beginners?
Both are excellent, very similar beginner strains. B+ trends slightly smaller and more uniformly ellipsoid; Golden Teacher trends slightly larger with a subellipsoid shape. B+ typically carries the higher spore density of the two, which some researchers prefer for high-volume slide prep. Many keep both on hand as a comparison pair.
QHow long does a B+ spore syringe last?
Under proper storage — 2–8°C, complete darkness, needle cap on, stored upright — a B+ spore syringe should remain viable for 12–18 months or longer. Never freeze it, as ice crystals permanently damage spore walls.
QIs B+ a good first strain for beginners?
Yes — it's one of the two most commonly recommended starter strains alongside Golden Teacher. Its very high spore density makes slide preparation forgiving, so new researchers get usable, confidence-building results quickly.
QCan you tell B+ apart from other cubensis strains under a microscope?
Not definitively at the strain level. All Psilocybe cubensis strains share the same species-level spore features. What's observable are subtle differences in average size, shape consistency, and deposit density — B+'s exceptionally dense deposit is one of its more recognisable traits, but it's not a substitute for documented provenance.
