 Short-fringed knapweed
Centaurea nigrescens Willd.
Family: Asteraceae 
Description and Life Cycle:
Short-fringed knapweed is a taprooted, herbaceous perennial that measures 30 - 150 cm tall.
The plants can have one or several openly branching erect stems and can be smooth or sparsely
hairy. Basal leaves are broadly elliptical-shaped, measuring 5 - 15 cm long and up to 3 cm
at their widest point. They have smooth margins, deep to shallow lobes or irregular pinnate
cuts. Basal leaves may also be smooth or lightly hairy on their undersides. Stem leaves are
lanceolate shaped and lack stalks and gradually become smaller moving up on the plant. Flowers
are present from June through September. The blossoms are pink-rose coloured (rarely white),
1.5 - 2.0 cm across and arise from a rounded, egg-shaped base. Individual bracts widen at the
upper tips and have dark coloured (almost black), tattered or comb-like spines. The lighter
areas of the bracts are not completely covered by the dark spines, which give the plant a "spotted
look". Seeds are tan coloured, 2.5 - 3.0 mm long with fine hairs. Pappus is absent or limited
to many irregular bristles 0.5 - 1.0 mm long. Each seedhead produces 22 to 44 seeds.
Note: Short-fringed knapweed is often confused with black knapweed.
British Columbia Biological Control Agents
References
Douglas, G. W., G. Stranely, D. Meidinger and J. Pojar, eds. 1998. Illustrated flora of
British Columbia. Volume 1. Gymnosperms and Dicotyledons (Aceraceae through Asteraceae). Govt.
of BC., Min. Environ. Lands and Parks and Min. For.
Flora of North America. 2007. 9. Centaurea nigrescens Willdenow, Sp. Pl. 3: 2288.
1803. November 9, 2007. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=200023639
MFR staff observations and comments
Tyrol Knapweed (Centaurea nigrescens Willd.). 2003. Nearctica.com, Inc. 2008-02-06.
http://www.nearctica.com/flowers/composit/thistle/centaur/Cnigres.htm
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