Random Plant: Spotted knapweed

Flower of a spotted knapweed (Centaurea stoebe ssp. micranthos, Asteraceae) photographed 09/17/2010 near Manitou Beach Michigan.

While I know this plant is spotted knapweed (Centaurea stoebe ssp. micranthos, Asteraceae), there seems to be some confusion about the specific taxonomy.  Most authorities seem to list it as C. stoebe ssp. micranthos but others call it C. maculosa.  According to the USDA they’re synonymous, but I don’t know the source of the conflicting nomenclature.

Leaf of a spotted knapweed (Centaurea stoebe ssp. micranthos, Asteraceae) photographed 09/17/2010 near Manitou Beach Michigan.

There are perhaps 600 known species in this genus, and some of them are native here in southern Michigan.  This particular knapweed is an invasive species.  It was probably introduced from Europe in contaminated seed in the late nineteenth century, and has since spread across the continent.  It gets a foothold in disturbed areas, and once established it can outcompete native plants and spread rapidly.  Biocontrol agents have been used to fight this invasive, including weevils, flies, and moths.

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About Jeremy Sell

Science and nature nerd.
This entry was posted in Botany, Random Plant and tagged , , . Bookmark the permalink.

2 Responses to Random Plant: Spotted knapweed

  1. It’s such a pretty flower: too bad it’s not only nonnative but also invasive. Here in central Texas we have a different invasive member of the genus, Centaurea melitensis, the Malta star-thistle. On the positive side, which is to say the native one, we have the larger-flowered and more attractive Centaurea americana. According to the USDA distribution map, it has been found in eastern Wisconsin, but not yet in Michigan. If you’re not familiar with it, you can see a picture at

    http://portraitsofwildflowers.wordpress.com/2011/06/04/basket-flower

    Like

  2. Jeremy Sell says:

    Nope, haven’t come across that one yet.

    Like

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