Centaurea jacea L., 1753

Common names

🇬🇧 Brown Knapweed
🇫🇷 Centaurée jacée, Tête de moineau, Ambrette

Taxonomy

Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Superasterids
Clade: Asterids
Clade: Campanulids
Order: Asterales
Family: Asteraceae
Subfamily: Carduoideae
Tribe: Cardueae
Subtribe: Centaureinae
Genus: Centaurea
Species: Centaurea jacea

Presence

Present.

Conservation status

Red List (Metropolitan France): LC Least Concern

Notes

Possible confusion with C. decipiens Thuill., 1799 or C. nigra L., 1753, whose flowers have phyllaries with a ciliate appendage, while those of C. jacea have phyllaries with an entire or lacinate appendage.

Possible confusion with C. timbalii Martrin-Donos, 1862, which has grayish-green, narrow top cauline leaves (< 5 mm), while C. jacea has light-green, broad top cauline leaves (> 5 mm).

Some plants have fimbriate appendages, with an appearance intermediate between C. jacea and C. decipiens. This could be due to introgression from C. decipiens (Tison & de Foucault, 2014), which is itself likely a stabilized hybrid of C. jacea × C. nigra. This kind of specimen is quite common in south-west France, especially in mixed populations where “pure” C. jacea specimens are rarer.

Their appearance is somewhat similar to the hybrid C. × gerstlaueri Erdner, 1905 present in North America and considered an invasive species in several places, and native to France and neighboring countries; however, its presence in France is not usually recognized and the treatment of these specimens remains problematic. This hybrid could be the one from which C. decipiens originates.

The following infraspecific taxa are accepted: