McKennaii Spores UK: Microscopy Guide

What McKennaii is called and where the name comes from

McKennaii is a strain name used for Psilocybe cubensis. The species has a formal history. Franklin Sumner Earle described it in 1906 as Stropharia cubensis, in Cuba. Rolf Singer moved it into the genus Psilocybe in 1949.

A strain name is an informal label. It is not a species name. A 2025 review in the Journal of Fungi describes dozens of strains as informally recognised. Most of its strain examples come from non-academic, community-based reports. The same review says commercially labelled cultivars often lack genetic similarity across different suppliers.

The name McKennaii is a trade name used by sellers. Double Blind Magazine says the name refers to Terence McKenna. The same article gives two origin stories and says it is unclear which is true. This guide does not choose between them.

This guide does not name a breeder or a collection site for this shop’s stock.

What to look at under the microscope

Use a microscope with an oil immersion lens. Michael Kuo describes this as a lens that magnifies about 1,000 times. The shop’s product page for this strain gives a range of 400 to 1,000 times. It recommends oil immersion at 1,000 times.

Record five things on each slide.

• Spore shape.
• Length and width.
• Colour under the lens.
• Wall thickness.
• The germ pore.

The product page names three study aims. They are comparing spore shape, wall thickness and geometry between strains. They are training in high-magnification slide work. They are classroom demonstrations of germ pore identification.

The reference range below belongs to the species, not to McKennaii.

Across Singer and Smith (1958) and Batista et al. (2025), published figures run from about 11.5 to 17 by 6 to 11.5 µm.

A 2025 review describes the spores as elliptic, with a germ pore. It adds a yellow-brown tint in KOH solution. That is a reason to measure your own slide.

Kuo’s method is simple to follow. Calibrate the eyepiece scale against a stage micrometer slide with known values. Measure mature spores only. Kuo suggests 10 to 20 measurements, and others recommend more. Report length and width as ranges, for example 7 to 9.5 by 4 to 5.5 µm.

Kuo also suggests making at least one mount in Melzer’s reagent. It shows whether the spores are amyloid, inamyloid or dextrinoid. Record the result beside your measurements.

This guide does not list spore measurements for McKennaii. None were found in the public sources used.

How McKennaii compares with Golden Teacher

Golden Teacher is the nearest strain on this shop’s own pages. The McKennaii product page names Golden Teacher first among the strains to study alongside it. It also lists a Golden Teacher syringe to compare side by side.

Both are Psilocybe cubensis. Both fall under the same species-level description above. This guide does not claim a measured difference between them. No public source was found that compares their spores.

To compare them yourself, keep every step the same. Use one microscope, one objective and one calibration. Mount both in the same medium. Measure 10 to 20 mature spores from each slide. Compare the ranges, not single spores. If the ranges overlap, the slides do not separate the two names.

Note these details on each slide label. Write the strain name, the date, the objective, the calibration value and the mounting medium. Add the number of spores measured. Another reader can then repeat your work.

A result describes the syringe on your slide. It does not describe every syringe sold under the same name. Read the Golden Teacher microscopy guide for the same comparison from the other side.

Syringe sizes offered

The product page lists two sizes, 10ml and 20ml. The sizes differ in volume. This guide makes no claim about spore counts per millilitre.

The syringes are prepared in the UK. Each syringe comes with a sterile needle and an alcohol prep pad. Store it refrigerated at 2 to 8°C. Do not freeze it.

Prices and stock are shown on the McKennaii spore syringe page. More guides of this kind are in the Learn section.