Data Views Total Plants: 2 CSV Excel PDF Click on column headings to sort table by that column Plant Part All Root Stem Low PPM High PPM StdDev *Reference Trifolium pratense Stem -- 418.0 * Trifolium pratense Root -- 221.0 * *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.