The seed megagametophyte from 69 trees of seven populations of Cupressus bakeri Jepson was analysed for fatty acids by gas-liquid chromatography. Compositional variability was very small. Most fatty acids were unsaturated. Identified by GC retention times and mass spectroscopy were palmitic, stearic, arachidic, oleic, linoleic, cis-11-eicosenoic, cis-11,14-eicosadienoic, cis-5,11,14-eicosatrienoic, cis-11,14,17-eicosatrienoic, cis-5,11,14,17-eicosatetraenoic, cis-5,11-eicosadienoic, margaric,behenic, lignoceric and vaccenic acids, the last five in very small or trace amounts. In canonical discriminant analysis most populations separated significantly from each other; the separations obtained did not convincingly populations separated significantly from each other; the separations obtained did not convincingly substantiate the existence of the ssp. matthewsii and typica proposed by Wolf.