Echinacea botany, taxonomy and distrubution
Echinacea species, collectively known as purple coneflowers, are native to North America and are distributed from southern Alberta south to the Gulf coast of Mexico, east to the Carolinas and west to the Rocky Mountain foothills (Urbatsch et al. 2006 ). Species within this genus are found in diverse habitats which include dry and mesic prairies, oak savannahs, and barren woodlands. Echinacea are placed in the sunflower tribe (Heliantheae, subtribe Rudbeckiinae). The circumscription of the genus has been problematic, presumably due to its recent divergence in North America, compounded by incomplete lineage sorting, hybridization and backcrossing following secondary contact (Hawkins et al 2008). Using morphometric methods, the genus has been variously delimited as consisting of nine species and four varieties (McGregor 1968) or as four species and eight subspecies (Binns et al. 2002). While sequenced-based phylogenetic studies failed to resolve the species relationships (Flagel et al. 2008), a chemotaxonomic study and an AFLP analysis supports McGregor's 1968 classification (Kim et al. 2004; Wu et al. 2009).

Echinacea genetics
All Echinacae species with the exception of E. pallida, are thought to be diploids. Chromosome numbers of E. purpurea and Echinacea angustifolia var. angustifolia are 2n=22 (Qu et al. 2004). Echinacea pallida is a tetraploid (2n=44), suspected to be a cross between E. simulata and E. sanguinea (McGregor 1968).

Echinacea economic use
Echinacea species are the sixth most popular botanical supplement in the U.S. (Blumenthal et al. 2011). Within the plant's distribution, Echinacea species was used for centuries by Native American tribes as a painkiller and an anesthetic to treat a wide variety of ailments ranging from snake bites to toothaches (reviewed in Kindscher 1989). Today, Western cultures use Echinacea mainly to treat upper respiratory infections despite a consensus of its efficacy (Percival 2000; Goel et al. 2004; Barrett et al. 2010). Echinacea species are also an important ornamental species and several selections based on novel flower colors have recently been released.

• Germplasm of Echinacea species (157 accessions) is available from the USDA here.
• The Medicinal Plant Genomics Resource is sequencing Echinacea purpurea. No sequence data from E. purpurea have been released as of 10/2011. Information on this project can be found here.
• Additional assembly information: download here

Using Illumina technology, the CGP has sequenced roots, leaves, seeds, flowers and stems from Echinacea angustifolia. These EST sequences are being assembled.

Barrett, B., Brown, R., Rakel, D., Mundt, M., Bone, K., Barlow, S., and Ewers, T. 2010. Echinacea for treating the common cold. Annals Int Med. 153:769-777.

Binns, S.E., Baum, B.R., and Arnason J.T. 2002. A taxonomic revision of Echinacea (Asteraceae: Heliantheae). Systematic Bot 27:610-632.

Blumenthal, M., Lindstrom, A. Lynch, M.E. and Rea, P. 2011. Herb sales continue growth. HerbalGram 90:64-67.

Flagel, L.E., Rapp, R.A. Grover, C.E., Widrelechner, M.P., Hawkins, J., Grafenberg, J.L. Alvarez, I., Chung, G.Y., and Wendel, J.F. 2008. Phylogenetic, morphological and chemotaxonomic incongruence in the North American Genus Echinacea. Amer J Bot 95:756-765.

Goel, V., Lovlin, R., Barton, R., Lyon, M.R., Bauer, R., Lee, T.D. and Basu, T.K. 2004. Efficacy of a standardized Echinacea preparation (Echinilin) for the treatment of the common cold: a randomized, double-blind, placebo-controlled trial. J. Clin Pharm Ther 29:75-83.

Kim, D., Heber, D., and Still, D.W. 2004. Genetic diversity of Echinacea species based upon amplified fragment length polymorphism markers. Genome 47:102-111.

Kindscher K (1989) Ethnobotany of purple coneflower (Echinacea angustifolia, Asteraceae) and other Echinacea species. Economic Bot 43:498-507.

McGregor, R. 1968. The taxonomy of the genus Echinaceae (Compositae). University of Kansas Science Bulleting 48:113-142.

Percival S.S. 2000. Use of Echinacea in medicine. Biochem Pharm 60:155-158.

Urbatsch , L. E. , Neubig, K. M., Cox, P.B. 2006. Echinacea Moench, Methodus. In Flora of North America Editorial Committee [eds.], Flora of North America North of Mexico, vol. 21, 88 - 92, Oxford University Press, New York, New York and Oxford UK. Available at website http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=111203 [accessed 5 March 2012].

Qu, L., Wang, X., Hood, Eatherley, H., Wang, M., and Scalzo R. 2004. Chromosome karyotypes of Echinaceae angustifolia var. angustifolia and E. purpurea. HortScience 29:368-370.

Wu, L., Dixon, P.M., Nikolau, B.J., Kraus, G.A., Widrlechner, M.P., and Wurtele, E.S. 2009. Metabolic profiling of Echinacea genotypes and a test of alternative taxonomic treatments. Planta Medica 75:178-183.