Putative monoterpene synthase. Binds 3 Mg(2+) or Mn(2+) ions per subunit. Secondary metabolite biosynthesis; terpenoid biosynthesis. Homodimer. The Asp-Asp-Xaa-Xaa-Asp/Glu (DDXXD/E) motif is important for the catalytic activity, presumably through binding to Mg(2+). Missing Asp-356 and Thr-565 residues essential for gamma-terpinene synthase activity. Belongs to the terpene synthase family.