Updated: October 6, 2026
Mushroom spores are sold strictly for microscopy and research purposes only. Cultivation of Psilocybin-containing fungi is illegal in many jurisdictions. This page is not a guide to finding, growing, or taking mushrooms.
Short answer: Z-Strain, also written Z Strain, is a trade name for material sold as Psilocybe Cubensis (Earle) Singer. It is not a separate species, a published variety, or a recognised variant. Sellers tell three different stories about who made it: a breeder called "The Keeper," a Shroomery user called "Lipa" (credited with a Mazatapec × Thai Lipa Yai cross), or a relative of Golden Teacher. None of them cites a dated, primary record. Under a microscope, a sample shows the spore characters of P. cubensis, which cannot confirm the label or any cross.
Home » Strain Encyclopedia » Psilocybe Cubensis » Z-Strain
In this guide
- What Z-Strain is
- Taxonomy
- What is documented and what is lore
- Spore and cap traits
- Origin and cross claims, source by source
- Names and spellings
- Identifying it, and what a microscope can't tell you
- Examining a slide
- Mushly products
- Legal note
- References
- FAQ
What Z-Strain is
Z-Strain is one of many named lines of Psilocybe cubensis in Mushly's all-strains library. The name is a catalogue label used by spore sellers. It describes a product and not a taxon, and a letter in the name does not tell you what the line is. For the difference between a species and a trade name, see our species vs strain primer and the Psilocybe cubensis species guide.
"Z-Strain is a trade name for Psilocybe cubensis, not a species or published variety. Sellers credit The Keeper, a Shroomery user called Lipa, or a Golden Teacher link; no dated record settles it. Claims compared."
Taxonomy
| Rank | Entry |
|---|---|
| Kingdom | Fungi |
| Phylum | Basidiomycota |
| Class | Agaricomycetes |
| Order | Agaricales |
| Family | Placement varies by source: Index Fungorum, Species Fungorum and NCBI list Agrocybaceae, while Wikipedia and many other references use Hymenogastraceae |
| Genus | Psilocybe |
| Species | Psilocybe cubensis (Earle) Singer, Sydowia 2(1-6): 37 (1948) |
| Basionym | Stropharia cubensis Earle (1906), described from Cuba |
| Trade name | Z-Strain / Z Strain (informal) |
Species records: Index Fungorum 290107, the Species Fungorum synonymy and NCBI Taxonomy 181762. None lists Z-Strain.
What is documented and what is lore
| Question | Status |
|---|---|
| Is Z-Strain a species or published variety? | No. The only formal name is Psilocybe cubensis. |
| Who made it, and when? | Sellers disagree. No dated primary record is published. |
| Is it a Mazatapec × Thai Lipa Yai cross? | One seller says so. Others don't. Unverified. |
| Is it related to Golden Teacher? | One seller says it may be. Unverified, and disputed. |
| Spore size and shape | Published for the species only, with no Z-Strain-specific measurements. |
| Published literature using the name | PubMed returned no results for "Z-Strain" with Psilocybe when Mushly checked, and none is known. |
Spore and cap traits
Short answer: the published measurements describe the species, not this name.
Singer and Smith's 1958 Mycologia monograph (Mycological investigations on Teonanácatl) describes P. cubensis spores as:
- Size: 11.5-17.3 × 8-11.5 × 7-9 µm
- Surface: smooth, with a thick, complex wall
- Apex: truncate, from a distinct apical pore
- Colour in a mountant: dark yellow brown in KOH, dark olive brown in NH4OH
The KOH and NH4OH colours are mountant colours, not spore-print colours. The paper does not mention Z-Strain. Guzmán et al. (2012) give a second species-level range of (12-)13-15(-17) × 8-10(-11) × 7-9 µm.
Seller descriptions are not diagnostic. Caps are described as "golden brown" and "caramel-to-gold" (Spore Genetics), "classic golden-brown" (Basidium Equilibrium) and "light to golden-brown" (Fungi Myco). Those descriptions are not measurements, and they match many other cubensis lines. Sellers also say "dark purplish-brown" for spores, a print-colour description and not a measurement. None of the pages we checked gives a measured spore size for this label. Record what you actually see on your own slide.
Origin claims
Short answer: three stories, none with a dated primary record.
| Source | What it says |
|---|---|
| Spore Genetics | "Lab-bred by 'The Keeper' in the 1990s," and "a powerful lab-derived lineage." Names no parents. |
| Fungi Myco | "Popular belief is that it was developed by the renowned mycologist known as The Keeper," while others credit a named mycologist and a Golden Teacher relationship. Calls the background "indistinct." Gives no date. |
| Inoculate the World | "Originally created by a good friend of ours, who goes by the name 'Lipa' on shroomery"; "a cross between Mazatapec and Thai Lipa Yai"; and "a lot of misinformation on the true origins of this strain." Gives no date. |
| Basidium Equilibrium | Gives no origin, creator, date or parents. |
The sources do not agree. One of them admits its own account may be misinformation. A repeated claim is still one claim, and a handle on a forum is not a verified person. We do not state a breeder, a cross or a year as fact, and we do not repeat the claim linking the line to a named mycologist.
Names and spellings
Sellers use Z-Strain and Z Strain, and Mushly's pages use both forms. We use "Z-Strain" on this page. A shared name is not a lineage, so don't assume that another seller's "Z" line is the same product. Record the exact label, supplier and date on every sample.
Identifying it
Short answer: microscopy supports a species-level note, not a strain identity or a cross.
- What a match shows: smooth, thick-walled spores with a truncate apex and germ pore, within the published species range, support P. cubensis as the species to compare. Ramírez-Cruz et al. 2013 notes that spore characters overlap across Psilocybe.
- What it cannot show: that a packet is Z-Strain rather than another cubensis label, who made it, or whether it is any cross of named parents.
- Chemistry: Mushly makes no claims about the chemical content of Z-Strain. Some seller pages make potency claims, which we do not repeat, and no published laboratory analysis under this name is known.
Examining a slide
Follow the general method in our Golden Teacher guide and the mushroom spores guide, and then:
- Measure at least 20 spores (length × width) and record the magnification and mountant.
- Note the germ pore, the wall, and the shape in face and side view.
- Record the colour in the mountant and the print colour separately.
- Write down the exact label (Z-Strain), supplier and date.
- Remember the limit: a fit to P. cubensis does not prove the Z-Strain label or any cross.
Mushly products
Mushly offers Z-Strain as a spore syringe and as a spore print, and in a multi-pack with other lines, for microscopy and taxonomic study. Check size, price and availability on each product page. Browse them through our spore syringes and spore prints categories.
Legal note
Mushly offers spores for microscopy, taxonomy, and mycological research. Laws on spores, and on psilocybin-containing mushrooms, differ by country and by U.S. state, and cultivation of psilocybin- or psilocin-containing species is illegal under U.S. federal law and in many other jurisdictions. Check the law where you live before ordering.
Spore syringes · Spore prints · Mushroom spores for microscopy guide
References
- Index Fungorum 290107; Species Fungorum synonymy; NCBI Taxonomy 181762
- Singer, R. & Smith, A.H. (1958), Mycologia 50
- Guzmán et al. 2012, Mycotaxon 119: 65-81
- Ramírez-Cruz et al. 2013, Canadian Journal of Botany
- Seller claims (not papers, not verified): Spore Genetics; Fungi Myco; Inoculate the World; Basidium Equilibrium; Sporeworks (its page was not reachable)
What is Z-Strain?