Data Views Total Plants: 4 CSV Excel PDF Click on column headings to sort table by that column Plant Part All Essential Oil Husk Essent. Oil Root Essent. Oil Seed Essent. Oil Low PPM High PPM StdDev *Reference Zea mays Essential Oil -- -- * Zea mays Husk Essent. Oil -- -- * Zea mays Seed Essent. Oil -- -- * Angelica archangelica 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.