Data Views Total Plants: 23 CSV Excel PDF , Previous12 Show all rows. Paginate rows. Click on column headings to sort table by that column Plant Part All Essential Oil Flower Flower Essent. Oil Leaf Pericarp Plant Rhizome Root Root Essent. Oil Seed Wood Low PPM High PPM StdDev *Reference Zingiber officinale Rhizome -- -- * Zingiber officinale Essential Oil -- -- * Zingiber officinale Root Essent. Oil -- -- * *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.