Home / Magic Mushroom Spores / Psilocybe Cubensis / E4K

Microscopy spores Psilocybe Cubensis - E4K

Psilocybe cubensis

E4K

The "Extraterrestrial 4th Kind": a Texas flower-bed find reportedly flipped into one of the tallest cubes in the hobby. Drops a normal heavy purple-brown print despite a pale, bulbous wild mother.

★★★★★ 5.0 · 5 reviews

£8.00 – £16.00

Choose your format

Format

Clear

Some formats are out of stock

Want to know the moment it returns?

Sold for microscopy, taxonomy and collecting only. Not for cultivation.

UK lab-made
filled under laminar flow

Discreet post
plain packaging, tracked

The short version

E4K is a modern collector's line with an unusually well-told origin: a pale, bulbous wild cube reportedly found in a Texas flower bed in 2016, then isolated into something that looks like its opposite, a very tall fruiter with small bell caps. Despite the leucistic-leaning mother, the stabilised line is a normally pigmented Psilocybe cubensis that drops a heavy purple-brown print. The name is pure sci-fi fun, not science.

Straight talk

Fact vs. legend

There is a lot of folklore around this strain. Here is which bits are real, side by side.

What we actually know

E4K is a plain Psilocybe cubensis, an isolation rather than a separate species or a verified hybrid.
The community story is unusually specific for a modern name: a wild cube reportedly found in Texas in 2016, then isolated indoors by the mycology educator known as Willy Myco.
The original wild fruit is described as pale and almost white with a thick cap and an oddly bulbous, solid stem, while the stabilised line is reportedly the near-opposite: very tall with small bell-shaped caps.
Despite that pale-bodied mother, the isolated line is normally pigmented and drops a heavy dark purple-brown print, exactly like a textbook cube.
It bruises blue-green where handled, the standard Psilocybe reaction as enzymes convert psilocybin to psilocin, which then oxidises into blue pigments.

What the community says

The name is said to stand for "Extraterrestrial 4th Kind", a riff on the old close-encounter classification scale (in which the fourth kind means abduction), with sellers tacking grey-alien whimsy onto the name. Treat that as marketing flavour, not anything we are claiming.
The finder is usually named as a Texas grower going by "Texas Cubensis King" (TKK), said to have spotted it in an enriched flower bed at his old apartment complex around 2016. Colourful, widely repeated, and impossible to verify.
At least one seller instead calls E4K an unknown hybrid with suspected Mexican and B+ lineage, which flatly contradicts the wild-find story. The two tales cannot both be true.
It gets billed as a "wicked potent" strain. That is reputation talking. Independent of grow conditions, a cube is a cube, and we are not in the business of ranking spores by strength.

The story

The cube that became its own opposite

Most modern strain names come with no backstory at all, so E4K is a small treat: it arrives with names, a year, and a place. By most accounts the line begins in Texas around 2016, when a grower remembered online as Texas Cubensis King reportedly spotted an odd cubensis growing in an enriched flower bed at his old apartment complex. The story goes that this wild fruit looked wrong in an interesting way, pale and almost white, with a thick cap and a stubby, bulbous stem that was solid tissue all the way through rather than the usual hollow stipe.

He is said to have shared a print with the mycology educator Willy Myco, who took it indoors for several months of selection. The punchline collectors love is that the isolated line ended up the near-opposite of the mother that started it. Instead of short, pale and bulbous, stabilised E4K is apparently one of the tallest cubes going around, topped with small bell-shaped caps that open like little petals. Take the people and dates as community lore rather than documented mycology, because that is exactly what they are.

A pale, dumpy wild fruit turned into a tall, bell-capped show pony. If the story is true, E4K is proof of how much an isolation can move a single line.

The name is the joke

"Extraterrestrial 4th Kind" is a riff on the old close-encounter classification scale, where the fourth kind means an abduction, and the grey-alien patter sellers attach to it is pure flavour text. There is nothing alien in the biology: under the lens this is a clean Psilocybe cubensis with ordinary thick-walled, germ-pored spores. Worth flagging too that one seller tells a completely different tale, calling E4K a hybrid of Mexican and B+ stock. That contradicts the Texas find, and nobody has shown paperwork either way, so we treat the whole backstory as a good campfire story rather than fact.

The species

Meet Psilocybe cubensis

E4K is a collector’s line of a single, well-travelled species. Psilocybe cubensis was first written up in 1906 by the American mycologist Franklin Sumner Earle, from a specimen found in a cattle field in Cuba, which is where the name comes from. He originally called it Stropharia cubensis; Rolf Singer moved it into the genus Psilocybe in 1948.

The genus name is a tidy bit of Greek: psilos (“bare”) plus kubē (“head”), for the smooth, peelable skin of the cap, so the full name reads roughly as “the bare-headed mushroom from Cuba.”

Family: Hymenogastraceae (older books say Strophariaceae)
Genus: Psilocybe (Fr.) P. Kumm., 1871
Species: Psilocybe cubensis (Earle) Singer, 1948
Basionym: Stropharia cubensis Earle, 1906
This product: E4K, a collector’s cultivar of the species
Type locality: Cuba (where it was first named)

How you’d know it

Field marks

These describe the mature mushroom for reference and identification.

Small bell caps

The stabilised line is known for compact, bell-shaped to conic caps that open into a petal-like look rather than going broad and flat. Colour is a caramel to golden-brown, often a touch darker at the centre. Modest in diameter for a cube.

Tall, fibrous stem

The signature trait: an exceptionally long, fibrous stipe, white to off-white, reportedly far taller than most cubes. A leftover partial veil leaves a ring (annulus) that usually ends up dusted purple-brown from falling spores. Note this is the inverse of the squat, bulbous wild mother.

Darkening gills

Crowded and pale grey when young, ripening to deep purple-brown to near-black as the spores mature on the basidia. The colour change is your cue that a print will deposit cleanly.

Blue bruising

Handle the flesh and it bruises blue-green, the classic Psilocybe tell as psilocybin is enzymatically converted to psilocin, which oxidises into blue pigments. Vendor photos of E4K often show strong bluing on the stem.

Where it comes from

A dung-lover with a wanderer’s history

Psilocybe cubensis is coprophilic, a fancy word for dung-loving. In the wild it lives on the droppings of big grazing animals, classically cattle and water buffalo, fruiting from warm, humid pasture. It does not grow on wood and it does not partner with tree roots.

You’ll find it across the warm parts of the world: the Gulf Coast of the United States, Mexico, Central and South America, Southeast Asia and Australia. It was named from Cuba, but where the lineage truly began is an open question. A 2026 study describing its closest wild relative in southern Africa suggests the deep roots are Old-World, the mushroom having apparently travelled with grazing herds long before anyone gave it a Latin name.

The main event

Under the microscope

This is what you actually bought the spores for. Put a print or a drop from a syringe on a slide and here’s what shows up.

Shape & size. Smooth, thick-walled and subellipsoid, like a slightly squashed rugby ball, roughly 11.5–17 µm long by 8–11 µm wide (the figures Paul Stamets settled on).
The germ pore. Look for a single pale, flattened dot at one end. That’s the one thin spot in the wall where, in nature, a mushroom would begin, and a real cubensis hallmark.
Pale alone, dark in a crowd. A single spore looks honey-amber with the light behind it; only in a mass do they read deep purple-brown to black. So a near-black print but pale spores on the slide is normal optics, not a dud.
What you’ll need. Find the field at 100×, study shape and the germ pore at 400×, and get the wall crisp at 1000× under oil. A touch of methylene blue or KOH lifts the contrast.
The legal bit, and why it’s true. A dormant spore carries no psilocybin or psilocin at all; that chemistry only appears later in living tissue. That is exactly why the spores are legal to own and study in the UK.

Choose your format

Print, syringe, vial or swab?

Same lab-grade genetics in every option. The honest difference is shelf life versus how soon you’re at the scope.

Spore print

Keeps longest

Spores dropped straight onto sterile foil. Stored cool and dry it outlasts everything else here, so it’s the one to reach for if you’re building a collection to keep for years.

Spore syringe

Ready tonight

Spores suspended in sterile water, ready to go straight onto a slide. The quickest way to be looking down the microscope this evening. Comes in 3 mL and 12 mL.

Vial & swab

Compact

A sealed glass vial is a tidy middle ground; a sterile swab is the most travel-friendly, robust little format for adding a strain to your reference set.

At a glance

The spec sheet

Species: Psilocybe cubensis
Strain: E4K (collector’s cultivar)
Spore print: Dark purple-brown to near-black, heavy depositor
Spore shape: Subellipsoid, smooth, thick-walled, with a germ pore
Spore size: ~11.5–17 × 8–11 µm
Basidia: Mostly 4-spored, ~20–30 × 7–10 µm
Wild habitat: Coprophilic, on herbivore dung & warm pasture
Climate: Subtropical to tropical
Intended use: Microscopy, research & collecting only

Dig deeper

Frequently asked

Yes, for microscopy and research. A dormant spore contains no psilocybin or psilocin, so the spores themselves are not a controlled substance in the UK. We sell them strictly for microscopy, taxonomy and collecting, never for cultivation.

By the usual telling it stands for "Extraterrestrial 4th Kind", a sci-fi nod to the close-encounter scale with some grey-alien whimsy attached by sellers. It is a fun name, not a description of anything you will see down a microscope. The spores are textbook Psilocybe cubensis.

No. The wild fruit it reportedly came from was described as pale and almost white, but the isolated line that circulates today is normally pigmented and drops a heavy dark purple-brown print. So expect a rich, easy-to-read print rather than the faint deposit a true albino or leucistic line would give.

We cannot prove either. The widely repeated version is a 2016 Texas wild find isolated by Willy Myco. At least one seller instead calls it a Mexican and B+ hybrid. Those contradict each other and neither comes with evidence, so we present both as community lore.

Smooth, subellipsoid, thick-walled spores, pale amber alone and dark purple-brown in mass, each with a small flattened germ pore at one end. Find them at 100x, study them at 400x, and get the wall sharp at 1000x under oil immersion.

Cool, dark and dry. A fridge (not freezer) suits syringes and vials; prints keep happily in a sealed bag somewhere cool. Stored well, a print stays viable for study for years.

Ask the community

Questions and answers

No questions yet. Yours could be the first.

For microscopy, taxonomy and collecting only.Sold for legal research. Not for cultivation. Spores contain no controlled substances. We trust you to be responsible.

E4K