If we follow the the instructions for creating a species list for a vice county, there is one additional step, which is adding a ‘subdivide’ clause via more options > grouping.
‘Subdivide’ adds additional columns to the output of the query, giving the number of records for each taxon in each date class period.
This query can be modified to give a count of hectads for each species in each date class, by adding a more options > grouping > distinct clause to the query, and selecting hectad.
Because old historic records are often only available at hectad resolution (at best) running this query at the hectad precision level is sensible as it allows comparison over many decades.