Plant lipids take the form of Omega 3, Omega 6, and Omega 9 essential fatty acids, the ratios of which are determined by the plant's stage of development and the specific part of the plant in which the oils are found.
Omega 3's oxidize readily and are usually found in the highest concentrations in the green and growing vegetative tissue, while Omega 6's are more stable and are concentrated in the seeds. Early in the plants life, it produces mainly Omega 3 fatty acids, but converts them to predominently Omega 6's as it nears maturity, in order to build a stable and long lasting energy supply into its seeds.
Both of these lipid types are healthy and necessary in our diets in the appropriate amounts. Our challenge today is that we consume an imbalanced diet with a disproportionate amount of Omega 6 fatty acids compared to Omega 3's, simply because we consume a disproportionate amount of grains.