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Native Centaurea?

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  • Leo Shapiro
    Sam et al., Just to confirm Joe Metzger s comment and clarify further: According to the treatment of Centaurea in Flora of North America (volume 19, 2006),
    Message 1 of 5 , Apr 15, 2008
      Sam et al.,

      Just to confirm Joe Metzger's comment and clarify further: According to the treatment of Centaurea in Flora of North America (volume 19, 2006), which is about as authoritative and up-to-date a reference as one could hope for, the genus is native to Eurasia and North Africa and ALL the North American species are introduced. Taxonomic boundaries have been very challenging in this group, but molecular phylogenetic work has apparently indicated that the two native North American "Centaurea" (americana and rothrockii) should be moved to their own genus (Plectocephalus) (assuming a goal of monophyletic taxonomic groupings...). 

      According to Flora of North America, P. americanus is a species of grassland habitats of the southern Great Plains and P. rothrockii is largely restricted to moister canyon sites in the Sierra Madre Occidental of Mexico and associated ranges of the American southwest. Both species may escape from gardens outside their native range...

      Leo Shapiro

      On Apr 15, 2008, at 3:33 AM, Joe Metzger wrote:

                As far as I can tell, there are NO native species of Centaurea in the northeast quarter of the NA. By the northeast I'm including everything east of the Mississippi and north of the VA/NC border. Herbaceous Plants of MD lists 8 species and notes that they are all exotic. If by Black Knapweed, you mean C. nigra, it is NOT Native. Gray's Manual of Botany lists 12 and only the last one C. americana is considered native and its range is west of the Mississippi coming as far east as Missouri.
                                                                            Joe Metzger

      To: beemonitoring@ yahoogroups. com
      CC: beemonitoring@ yahoogroups. com
      From: sdroege@usgs. gov
      Date: Mon, 14 Apr 2008 10:20:44 -0400
      Subject: [beemonitoring] L. chrysurus and Centaurea

      Thanks folks for sending in more information about Centaurea issues.  There certainly are many railroads in that region.  At one time Lehigh Gap had 4 separate lines going through it.  At this point they just have 2, one on either side of the river.  I think that it might be useful to organize a couple of survey days in the region using RR Tracks as the targeted survey area.   

      I wonder if the native Black Knapweed (an excellent bee plant) has suitable pollen for L. chrysurus.  I have assumed that this is the species I see along dry road cuts in the Appalachians. ...but perhaps it is Spotted Knapweed. 


      Sam Droege  Sam_Droege@USGS. GOV                      
      w 301-497-5840 h 301-390-7759 fax 301-497-5624
      USGS Patuxent Wildlife Research Center
      BARC-EAST, BLDG 308, RM 124 10300 Balt. Ave., Beltsville, MD  20705
      Http://www.pwrc. usgs.gov


      Chapter 1: The Planting
             "Cultivation: nothing gained but arrowheads"
             "The planter's elegant swipes"
             "Something like a weaving or a web"
             "A marked absence of horses"
             "Scholia on silence: somew! he! re in the distance"
      Chapter 2: The Ordered Meadow
             "Soybeans: a dance field snake green"
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      Chapter 3: A Question of Horizon
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      Andrew Grace

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