Include only mature pilei in your measurements. When the pileus is immature, the partial veil (when present) is still intact, and the pileus often has the margin quite incurved and close to the stipe.

For measurement features we recommend entering the midpoint of the observed range. Thus, if the range is 20-60 mm, enter the value 40. Alternatively, you may enter the full range, but this will tend to retain more taxa, including those that overlap only slightly with the entered range. Entering the value for the smallest or largest individual is not recommended because exceptional individuals may be outside of the coded range for a taxon, whereas the midpoint of the observed range is unlikely to fall outside the coded range.