This paper, published last month by Czech researchers in the International Journal of Molecular Sciences, aimed to quantify the concentrations of five tryptamines - psilocybin, psilocin, baeocystin, norbaeocystin, and aeruginascin - in a range of psychedelic mushroom species.
Somewhat unsurprisingly, the highest concentrations of psilocybin and psilocin [..] were found in the Psilocybe species, particularly Psilocybe serbica var. bohemica (common in the Czech Republic, and collected by the authors themselves), Psilocybe semilanceata (better known as Liberty Caps), and Psilocybe cyanescens (Wavy Caps).