The fruiting body development of Ps1locybe cyanescens mushrooms begins with the primordia, which are approximately 2 x 2 mm in size. The primordial universal veil and the primordial bulb are already differentiated at this stage. At the apex of the primordial bulb, the hyphae are in an active growth state and gradually differentiate into the cap and stem primordium. 

As the cap primordium continues to develop, the hymenophoral primordium appears, where the gills form. Radially arranged, vertical, thin plates made of yellow to brownish, more or less irregularly arranged, degenerating hyphae form at regular intervals in the hymenophoral primordium. These hyphae are separated from the vital hyphae segments by septa and disappear during the further development of the hymenophoral primordium.

This separates the primary gills from each other. The vital terminal hyphae segments, delineated by degenerating hyphal fragments, branch out and form the young hymenium through regular subterminal or subbasidial branching. The formation of the gills progresses towards the gill edge, the cap context, or in both directions. The primordial universal veil on the upper part of the fruiting body primordium deteriorates in the early stages of fruiting body development, so that there are usually no remnants on the mature cap and may only remain on the stem.

As development progresses, the volume of all parts of the young fruiting body increases. The stem thickens through the swelling and elongation of the terminal cells in the hyphal network, while the cap volume increases as the cap stretches. Shortly after the cap expands, the basidia begin to produce spores.