Count the number of sterigmata per basidium. Sterigmata are the small projections at the apex of basidia, upon which spores are produced. Sterigmata can be viewed on basidia loose in a squash preparation of a lamella, or seen in top view by looking at the face of an intact lamella. Often there are developing spores attached to basidia. If viewing basidia side-on, in certain orientations the upper two sterigmata of a four-spored basidium can obscure the lower two sterigmata, which can be observed by focussing downwards.

Where there is a mixture of basidia with different numbers of sterigmata, choose the dominant number.

Choose this state if: the predominant number of sterigmata on the basidium is four. This is the normal state for most agarics.