230 K<BR>250<BR>28 K<BR>309 K<BR>Giant ragweed<BR>450 K<BR>Number of Seed Produced per Plant  <BR>Ragweed = Harrison et al. 2001; johnsongrass = Warwick and Black (1983); horseweed = Regehr and Bazzaz (1979); waterhemp = Nordby and Hartzler (2004);  Palmer amaranth = Macrae et al (2009).<BR>Johnson-grass<BR>Horseweed<BR>Waterhemp<BR>Palmer amaranth<BR>