Yes, they are a cultivar group, in this case it means that from the original Shirley Poppy, (common name) some hybrids have been discovered or hybridized and named. So yes, for the un-named Shirley Poppies, they should have their own entry but 'Shirley Poppy' isn't technically a cultivar name by itself because of the wide varieties in colors.
If you look at the bottom of the list for the poppies, you'll see where the Shirley Poppy
Papaver rhoeas named ones start with 'American Legion'.
http://garden.org/plants/brows...
If you do some research on the cultivar names, you could probably find out which cultivar class they belong to, with the Shirley Poppy
Papaver rhoeas or the Flanders Field Poppy.The common name Flanders Field Poppy and Shirley Poppy seem to be mistakenly grouped together everywhere, including the database here.
One distinction noted here from that link posted by Myriam, bonitin.
According to the original grower of the Shirley Poppy, "When later writing on the subject, he set out what might be said to be the specification for his Poppy.
He said...
"Let it be noticed that true Shirley Poppies...
(1) are single, (2) always have a white base with (3) yellow or white stamens, anthers and pollen, (4)
never have the smallest particle of black about them.
Double Poppies and Poppies with black centres may be greatly admired by some, but they are
not Shirley Poppies."
So it already looks like some images may have to be edited out.
