Pseudoivalin, (Ib), previously obtained from Iva microcephala Nutt., and pseudoivalin acetate (Ia) have been isolated from the leaf and stem wax of Calocephalus brownii F. Muell. (family Compositae). A structure for calocephalin, C17H22O5 a new sesquiterpene lactone also present in the wax, is deduced from spectroscopic evidence.