Data Views Total Plants: 201 CSV Excel PDF , Previous1..234567891011 Show all rows. Paginate rows. Click on column headings to sort table by that column Plant Part All Bud Bulb Flower Fruit Fruit Juice Herb Leaf Plant Pollen Or Spore Rhizome Root Seed Shoot Sprout Seedling Tissue Culture Tuber Low PPM High PPM StdDev *Reference Harpagophytum procumbens Root -- -- * *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.