Psilocybe subaeruginosa is a highly potent mushroom native to Australasia and New Zealand with a mildly floury scent and flavour. While containing low levels of psilocin, it derives its potency from very high quantities of psilocybin as its active compound. Because of this, it has a strong bluing reaction that is characteristic of potent members of the Psilocybe genus.
This species has few distinct characteristics that separate it from oother mushrooms aside from its natural range. It can have an average to long stipe, up to 22 cm, with occasional rhizoids (root-like structures) near the base. The cap usually has a slight umbo and the edges can lift up in aged fruiting bodies.
P. subaeruginosa has a distinct preference for where it grows, frequently on woody debris from the months of April to August. It is found on fresh or decaying wood chips and mulch, a common visitor in pine tree plantations. With spores of this species readily available online, it is suitable for outdoor cultivation in many temperate areas, similar to P. azurescens.
Further, P. subaeruginosa is highly similar in appearance to numerous other species inside and outside its natural range. Outside the Psilocybe genus, Pholiota communis (non-toxic but not psychoactive) and Galerina marginata (highly toxic) have similar features, along with other members of the Galerina genus.
Within its range, it is frequently confused with Copelandia or Panaeolus cyanescens, another psilocybin-containing mushroom. As a coincidence, this species is also very similar to P. cyanescens, preferring a similar habitat, and is considered a “sister species” along with P. azurescens.
To add to any confusion that may arise, P. subaeruginosa is likely to include sub-species which were once considered independent. P. australiana, P. eucalypta and P. tasmania are all suspected to now be the same, highly variable, species P. subaeruginosa.
While the identification may be challenging, as well as finding these mushrooms outside of their natural habitat, their potent nature is worth the trouble.