Centaurea jacea L.

brown knapweed

Pastures, successional fields, roadsides, and disturbed areas. A very common weedy species sometimes forming dense patches but mostly thinly distributed throughout an area. Many plant show introgression toward C. nigra even when C. nigra is not nearby. These individuals probably represent the morphologically variable nothospecies C. x moncktonii.

Forb/herb

Perennial

Vascular

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The Centaurea jacea complex which is European in origin is a difficult group due to hybridization, polyploidy, apomixis, and morphological variation (see Keil and Ochsmann [2006] for a brief overview). Keil & Ochsmann (2006) in FNA follow the “traditional approach for North America” and recognize three species (C. jacea, C. nigra, and C. nigrescens) and a nothospecies (C. x moncktonii). This does align (albeit with some modifications) with Fernald (1950) and Gleason and Cronquist (1991). We also follow this approach.

Not Native Naturalized FACU (NWPL EMP) FACU (NWPL NCNE) SNA (State Rank) GNR (Global Rank)

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