Amaranthus Flour

A friend of mine is telling me that the plant Kiss Me over the Garden Gate is an Amaranthus. She told me you can eat this and make flour from it. I have never heard this in conjunction with this plant, and cannot find information on it anywhere. Can you help me?

Amaranthus species produce nutrituous seeds that have been used for centuries as a grain for consumption. We carry the species most often used for this purpose, grain amaranth (A. hypochrondriacus). For more information please see our online catalogue:
www.richters.com/Web_store/web_store.cgi?product=X8012
For other Amaranthus species in our catalogue, please see the vegetable amaranth:
www.richters.com/Web_store/web_store.cgi?product=X8010
and love-lies-bleeding:
www.richters.com/Web_store/web_store.cgi?product=X7648