Australia is the centre of origin of wood-loving magic mushrooms

A. K-means test for number of groups in the data. The number of populations can be estimated from the 'elbow' in the graph. B. Sampling of P. subaeruginosa from Australia. C. DAPC analysis with facets designated by the final cutoff for K. Each horizontal row shows how the overall dataset changes if a population is split from the rest (new colours in each row are the 'new' population). D. SplitsTree network of relationships among 1.5 million SNPs in the Australia population of P. subaeruginosa, with three genomes of wood lovers from the Northern Hemisphere. Several of these populations include sibling genotypes (specifically Ravensbourne, Kunyanyi, Ellendale, Dynnyern, Clifton Hill).

Another sub season is soon upon us. The story of how populations of P. subaeruginosa are structured in Australia is quite clear, even though we're missing samples from the entire length of NSW. Populations are structured by geography, with some localised, mountain-top populations in Queensland having few opportunities for outcrossing. Populations in southern Australia are divided by a mountain range. There is evidence of distribution of P. subaeruginosa in mulch, for example, the populations from Clifton Hill and Geelong (both mulched garden beds).

It's been fantastic to speak with the collectors of these mushrooms. Based on their information, it is likely mycelium of P. subaeruginosa is persistent from year to year. This persistence keeps the same genotypes at the same locations, which is different to P. cubensis for which genotypes are ephemeral and dependent on spore distribution in manure (in my opinion). A comparable example to P. subaeruginosa is the humungous fungus among us, which is a huge clonal network of mycelium. Mycelia of P. subaeruginosa is ubiquitous in natural Australian environments, and those of you who re-visit mushrooms from season-to-season see the same genotype every time. There are opportunities for outcrossing, especially with mulch distribution and artificial movement of soils and wood chips.

Psilocybe azurescens and P. cyanescens are introduced to the northern hemisphere from Australia. They cluster nicely among our populations from Australia, although we weren't lucky enough to sample their exact provenance in this study. For context, much of the sampling is of siblings, sampled from sister basidiospores from single mushroom caps. Keep in mind that many of the genomes in this figure are offspring and that will put the genetic distance in context. The genome of P. subaeruginosa is about 50 million base pairs, and I'm looking at a tiny fraction of differences (1.5 million base pairs) to illustrate how these genomes are related. I think these data support P. subaeruginosa is one species and other related taxa are synonyms. My opinion is no indication of the future taxonomy, and many taxonomists prefer to split groups of microorganisms into different species.

There is a lot of variation at the psilocybin locus in our sampled populations of P. subaeruginosa. It's about to get interesting if we can link any of these variations to Wood Lover's Paralysis. Should have something for you in the next couple of weeks. 

The P. cubensis study is finished. It's sitting with my co-authors for their magic touch. Looking forward to sharing some new knowledge about mating in cubes with y'all as well :).