As mentioned the other day, Winterbourne hold
the National Collection of Anthemis:
In case you wonder, as I did, just what it means to hold the National Collection, this is what is written on the notice at Winterbourne:
"The Plant Heritage mission is to encourage the conservation of cultivated plants in the British Isles, preserving our magnificent plant heritage and educating the public in the importance of cultivated plant conservation. The National Plant Collections Scheme aims to create and maintain 'living libraries' or individual species cared for by dedicated specialist growers, individuals or organisations."
More details of National Collections can be found here: http://www.nccpg.com/National-Collections.aspx - including a list of endangered plants - important to know if you want to collect dye plants from the wild.