... In every case the avenaciolide from fed cultures was indistinguishable from a pure reference sample. Acknowledgementse thank Mr. TR Etherington for tech- nical assistance and the SRC for a Research Studentship (to PH). REFERENCES 'JH Bateson and BE Cross, 1. Chew. Soc. Perkin I, 1131 (1974). 'BE Cross and P. Hendley. Ibid. Perkin 1,2523 (1975). l. Brookes, BK Tidd and WB Turner, Ibid. 5385 (1963). . ...