Artemisia dracunculus is an accepted name .
http://www.theplantlist.org/tp...
Artemisia dracunculoides is a synonym of Artemisia dracunculus ...
http://www.theplantlist.org/tp...
But they are different, the French variety can't be grown from seed as it doesn't make any, suggesting it's a sterile hybrid perhaps initially occurring naturally. I found a pdf which tells more, it has a long history!
http://jhawkins54.typepad.com/...
Artemisia dracunculus var. sativa is the name given for French Tarragon but it's not included in the Plant List.
http://www.theplantlist.org/tp...
As found on mobot, Artemisia dracunculus 'Sativa' is given as a cultivar name.
http://www.missouribotanicalga...
