This feature refers to the shape of the pileus centre, rather than the overall shape of the pileus.

Choose this state if: there is a distinct, narrow papilla (mammilla) at the centre of the pileus, at most to about one-tenth of the diameter of the pileus (to 2 or 3 mm across on a small pileus of 30 mm, or to 10 mm across on a very large pileus of 100 mm diameter).

Other terms used to describe this state are mammillate or cuspidate (when the apex is drawn out into a long point).

If the projection is broader in relation to the pileus diameter, choose umbonate.