Echinacea is a genus of herbaceous flowering plants in the daisy family. It has ten species, which are commonly called coneflowers. They are found only in eastern and central North America, where they grow in moist to dry prairies and open wooded areas.

The generic name is derived from the Greek word ἐχῖνος (ekhinos), meaning "sea urchin", due to the spiny central disk. These flowering plants and their parts have different uses. Some species are cultivated in gardens for their showy flowers. Two of the species are listed in the United States as endangered species.

"Echinacea purpurea" is used in traditional medicine. Although commonly sold as a dietary supplement, there is insufficient scientific evidence that Echinacea products are effective or safe for improving health or treating any disease.

More Info: en.wikipedia.org