I always thought there was more in the stem then in the cap.
But:
The concentrations of psilocin and psilocybin, determined by high-performance liquid chromatography, were determined to be in the range of 0.14–0.42%/0.37–1.30% (dry weight) in the whole mushroom, 0.17–0.78%/0.44–1.35% in the...