Golden Teacher looks like any other Psilocybe cubensis: a cap that turns from brown to golden brown as it matures, grey gills that darken to purplish black, a white stem with a membranous ring, blue stains where the flesh is damaged, and a purple spore print. Shops describe its caps as golden and fairly large. None of those features separates it from other cultivars, and nobody can tell a cultivar by looking at it.
2.1The species picture
The standard description of Psilocybe cubensis goes back to Singer and Smith (1958) and is summarised on Wikipedia. These are the measurements and colours to expect, whatever the name on the kit:
| Part | What the description says |
|---|---|
| Cap | 1.6 to 8 cm across; conical to convex with a small central bump when young, broadly convex to flat later; smooth and sticky |
| Cap colour | brown, fading to white at the edge, becoming golden brown or yellowish with age |
| Gills | narrow, grey at first, darkening to purplish black and somewhat mottled; edges stay whitish |
| Stem | 4 to 15 cm tall, 0.4 to 1.4 cm thick, hollow, white, yellowing with age |
| Ring | a persistent white membranous ring, left by the veil that covers the young gills |
| Spore print | purple |
| Bruising | all parts stain blue when damaged |
2.2Where the gold comes from
The description above already contains the colour in the name: caps of P. cubensis become golden brown or yellowish as they mature. Rolf Singer even distinguished varieties of the species partly by cap colour, from brownish to pale to more yellow. A golden cap is a feature of the species and of the age of the mushroom. It tells you nothing about which cultivar you are looking at.
2.3What shops say about Golden Teacher
Product descriptions add a few features. Dutch-Smart's Royale Flush page mentions "golden-colored caps". Its XXL page calls Golden Teacher "the largest mushroom species in the collection" and gives a cap diameter of about five centimetres. Five centimetres sits comfortably inside the 1.6 to 8 cm range for the species, and "largest in the collection" compares cultures within one shop's range. Neither statement comes with measurements, and we found no published comparison of cap size between cultivars.
2.4The blue stains
Press or cut a cubensis mushroom and the damaged spot turns blue. In 2020 a group in Jena identified the chemistry behind it (Lenz et al., 2020). Two enzymes act in sequence: one removes the phosphate group from psilocybin, which turns it into psilocin, and the second oxidises psilocin. The oxidised molecules link into chains of three to thirteen units, and those chains are blue.
Two things follow from that chemistry. Blue bruising shows that psilocin was present and has been oxidised at that spot. And the psilocin that turned blue is no longer psilocin, so a heavily bruised mushroom has lost part of it.
2.5The spore print
Lay a mature cap gills down on paper or glass and it drops a dark purple print. The print is the same for all cubensis cultivars. According to a Czech laboratory study, the spores themselves contain no psilocybin or related tryptamines (Gotvaldová et al., 2021). That matters for the law, which is covered in lesson 6.
2.6Why you cannot identify a cultivar by eye
Cultivars of P. cubensis are closely related lines of one species, as lesson 1 explains. Within a single kit, young caps are conical and dark while older caps are flat and pale gold, so one harvest can look like two cultivars. Without a genetic test, the label on the box is the only evidence of what grew in it.
The same caution applies the other way round. Golden Teacher is a cultivated line; nobody finds it in a field. Identifying wild mushrooms takes a specialist field guide and experience, and a photo of a cultivated Golden Teacher is neither.
?Review questions
Answer for yourself first, then open the answer.
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Is a golden cap a sign that a mushroom is Golden Teacher?
Answer No. Caps of P. cubensis turn golden brown or yellowish as they mature, whatever the cultivar.
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What causes the blue stains on a bruised mushroom?
Answer Enzymes turn psilocybin into psilocin and then oxidise it; the oxidised molecules form blue chains.
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What colour is the spore print, and do the spores contain psilocybin?
Answer Purple. A laboratory study found no psilocybin or related tryptamines in the spores.
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Why can one harvest look like two cultivars?
Answer Young caps are conical and darker, older caps flat and paler, so age changes the look more than the cultivar does.