The invention relates to sesquiterpene synthases from Patchouli plants (Pogostemon cablin), and methods of their production and use. In one embodiment, the invention provides nucleic acids comprising a nucleotide sequence as described herein that encodes for at least one sesquiterpene synthase. In a further embodiment, the invention also provides for sesquiterpene synthases and methods of making and using these enzymes. For example, sesquiterpene synthases of the invention may be used to convert farnesyl-pyrophosphate to various sesquiterpenes including patchoulol, .gamma.-curcumene and other germacrane-type sesquiterpenes.