How Digitalis Has Been Hybridised And Improved.

Please could you tell me how digitalis has been hybridised and improved over the years?
Digitalis or common foxglove:

The original species D. purpurea (purple) has been around for a long time in fact there are references to it back in the 13th century.Although it is a British native plant,it also grows throughout Europe.There was also another species growing in Europe which was D.lanata. which tended to be smaller with slightly different leaves and more variation in colour.
The ancient apothecaries and herbalists were very interested in the medicinal properties of Digitalis so they began to cultivate it which has led to selection and development of better forms through the ages.The majority of changes would have been brought about more often than not by genetic mutation and the production of “sports” rather than planned
breeding,as foxgloves produce prodigious amounts of seed easily.In fact this is still happening today.The latest one being D.purpurea “Pam’s Choice” which is now in commercial production having been found growing a couple of years ago in someone’s garden.For More information
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