Seeds from Bevendean Down have been gathered and stored in the Kew's Millennium Seed Bank to preserve them for future generations.
The project aims to collect seeds from the country's best downland sites to create new wildflower sites in the city centre.
The seeds were collected with a special 'brush harvester' machine which brushes the top of the meadow to knock the seeds out and catch them.
Volunteers have also been hand harvesting seed that can not be collected mechanically, from a variety of sites.
Brighton and Hove City Council Leader Jason Kitcat said: "We are delighted that Kew has recognised how good the site is and have targeted it to use for seed collection for the Millennium Seed Bank. It's a fitting tribute to the hard work and team effort."