Data Views Total Plants: 1 CSV Excel PDF Click on column headings to sort table by that column Plant Part Low PPM High PPM StdDev *Reference Serenoa repens Plant -- -- Gruenwald, J. et al. 1998. PDR for Herbal Medicine. 1st ed. Medical Economics Co., Montvale, NJ. 1244 pp. (abbreviated as PHR or Physicians Herbal Reference in my mind) *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.