Tuesday, March 19, 2013

Weleda: Wrong centaury

Weleda is a company providing skincare, health, and beauty products based on natural ingredients and biodynamic principles.  They list their plant ingredients in an online dictionary (more companies should do this, it is an excellent resource), and get their botanical taxonomy mostly correct (with the exception of their capitalization of species epithets).

There are, however, one major mistake, and this is a mistake that is not uncommon.  The common name centaury is used for several unrelated plant genera, most commonly Centaurium (a gentian, in Gentianaceae), and Centaurea in the sunflower and aster family (Asteraceae).

The plant listed as "Centaury (Centaurium Erythraea)", should be Centaurium erythraea, but the photo at Weleda's website is of Centaurea cyanus, so the two genera are also mixed up.  It is simply the wrong species photo with the bitter-tasting Centaurium plant they use in their products.
Centaury, screenshot from Weleda.com
The common name for the blue-flowered Centaurea cyanus is often cornflower, since it is a common weed in grain fields in Europe (corn in Europe is not the same as American corn, that is called maize in Europe). Centaurium erythraea on the other hand is a pink-flowered herb that grows in meadows, roadsides, and slightly wet areas. 

The species epithet should be listed with a lower case letter in the beginning, as 'erythraea'.  Weleda gets this formatting rule wrong for most of its plant species names, but that is easy to fix. For example, 'Arnica Montana' should be 'Arnica montana' in the ingredient list to be accurate.

Common names that are the same for several unrelated species are not at all unusual; examples are snakeroot, hemlock, sycamore, and ironweed. One species can have several common names too, so common names can be very confusing. Only scientific names are unique to a species and universal and the same worldwide.  But more on that in a later post.