© Jörg Ochsmann 2001 


Ochsmann, J. 2001:
On the taxonomy of spotted knapweed (Centaurea stoebe L.). In: Smith, L. (ed.): Proceedings of the First International Knapweed Symposium of the Twenty-First Century, March 15-16, 2001, Coeur d’Alene, Idaho.  USDA-ARS, Albany, California. 33-41. [Download proceedings as pdf]

Spotted knapweed was introduced into North America as a seed contaminant from south-eastern Europe in the middle of the 19th century. Today it is a well-known noxious weed in USA and Canada causing economic problems by infesting farm land.
Native to western, central, and eastern Europe spotted knapweed consists of a group of closely related taxa. For the taxonomy and nomenclature various different concepts have been used by different authors resulting in great confusion.
During recent studies the delimitation of the different taxa of spotted knapweed was investigated by using morphological and molecular techniques. According to this work Centaurea maculosa LAM. (described from Central France), as well as C. rhenana BOREAU, are synonyms of Centaurea stoebe L. subsp. stoebe, which is native to western and central Europe only. These plants are biennial, strictly monocarpic and diploid (2n = 18). All the North American plants called “Centaurea maculosa” are perennial, polycarpic and tetraploid (2n = 36) and thus must belong to a different taxon. Parallel to the introduction into North America similar plants spread all over Europe. Molecular data confirm that the plants introduced into North America and into Europe belong to the same taxon. Their correct name is Centaurea stoebe L. subsp. micranthos (GUGLER) HAYEK (synonyms are “C. biebersteinii” and “C. micranthos”).

(Stand / last updated: 28.01.2007)