Data Views Total Plants: 2 CSV Excel PDF Click on column headings to sort table by that column Plant Part All Plant Shoot Low PPM High PPM StdDev *Reference Inula helenium Shoot -- 6.6 * Inula helenium Plant -- -- J.S. Glasby Dict.Pls Containing 2ndary Metabolite. 1991. *Unless otherwise noted all references are to Duke, James A. 1992. Handbook of phytochemical constituents of GRAS herbs and other economic plants. Boca Raton, FL. CRC Press.