The percentage of linoleic acid in corn germ oil of three crosses, C103D x B73, C103D x B84, and T220 x H51, and their reciprocals was investigated. Corn germ oil from F2, F3, and backcrossed generations was also examined. More than one gene locus appeared to be involved in conditioning the linoleic acid content in these crosses. Strong maternal effects were exhibited in the F1's. Genotype also superimposed variations in fatty acid compositions within the characteristic lipid class patterns of the phospholipids, phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol. Fatty acid placements in triglycerides, digalactosyldiglycerides, and phospholipids of one inbred, H51, were determined by lipase and phospholipase hydrolysis. The overall pattern of placement showed that the fatty acids at the 1 position were predominantly saturated saturated and those at the 2 position were predominantly unsaturated, but the fatty acid distribution was different for each individual lipid class. The molecular species of the phosphatidylcholines and phosphatidylethanolamines were separated by silver nitrate thin-layer chromatography. The major differences in the molecular species were a higher level of the dienoic-dienoic species and a lower level of the monoenoic-monoenoic species in the phosphatidylethanolamines than in the phosphatidylcholines.