Melmac Spores UK: Microscopy Guide

What Melmac is called and where the name comes from

Melmac is a strain name used for Psilocybe cubensis. The name Melmac is a trade name used by sellers. Double Blind Magazine says the name most likely refers to the fictional home planet of the character Alf. It also says the line was bred in a lab and was not found in the wild.

The same article says that, as the story goes, Melmac is a variant of Penis Envy. It also says some people think Melmac is closer to the original Penis Envy. It states that the validity of that claim is subject to debate. This guide gives the Penis Envy link as the story told about the 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 review also says commercially labelled cultivars often lack genetic similarity across different suppliers.

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

What to look at under the microscope

Start with the same features on every slide. These are spore shape, length, width, wall thickness and germ pore. Michael Kuo says to measure mature spores only. He notes that spore sizes in field guides describe mature spores.

Kuo suggests 10 to 20 measurements, and others recommend more. He reports length and width as ranges, for example 7 to 9.5 by 4 to 5.5 µm. Calibrate the eyepiece scale first. Use a stage micrometer slide with known values.

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.

The range below belongs to the species, not to Melmac.

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.

The species has a purple spore print. Your own slide is the better guide. A label such as Melmac tells you what a seller calls the syringe. It does not tell you the spore size. Only your own slide, measured with a calibrated scale, can do that.

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

How Melmac compares with Penis Envy

Penis Envy is the nearest strain here, for two reasons. This shop lists Melmac on its Penis Envy family page. The magazine article above also describes Melmac as a variant of Penis Envy.

Both are Psilocybe cubensis, so both fall under the same species-level description. 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 syringes in the same medium. Measure 10 to 20 mature spores from each. Compare ranges rather than single spores. If the ranges overlap, the slides do not separate the two names. Keep the focus and the lighting the same on both slides. Sketch or photograph one typical spore from each slide, beside the measured range.

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

The 2025 review reports that labelled cultivars often differ between suppliers. A result describes the syringe on your slide. It does not describe every syringe sold under the same name. Read the Penis Envy microscopy guide for the other side of the comparison.

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. They are sold for microscopy and research only. Open the Melmac spore syringe page for current prices and stock.

More guides of this kind are in the Learn section.