I think there is some confusion about their precise botanical name. I have seen them listed as Chrysanthemum rubellum in some catalogues but in others they are not chrysanthemums at all but Dendranthemas. I have been dreaming over the Bluestone Perennials catalogue today and there they use both names.
I have two varieties in my garden 'Clara Curtis' with deep pink flowers and 'Sheffield' which is a warmer, peachier pink. Both have simple daisy flowers. The first picture is Sheffield, the second Clara Curtis., taken with my Polaroid SX-70 camera.
You may be able to purchase them from a local nursery or even better take some slips from a friend. They are available from many mail order sources including Bluestone.
Wear flowers in your hair any time of year. This hat is stunning with its beautiful flowers and elegant flapper cloche shape. It is hand crochected and available at Mellisam4715 on Etsy.