There are often white flowering forms of Digitalis purpurea.

In the past these have been decribed as Digitalis purpurea f. alba, Digitalis purpurea var. albiflora or Digitalis purpurea f. albiflora, but not as Digitalis ssp. alba.

However all the names are now regarded as synonyms of Digitalis purpurea according to http://www.theplantlist.org/tpl1.1/search?q=digitalis+purpurea.

The observations will be swapped to Digitalis purpurea.