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y-Linolenic acid (6c,9c, 12c-18:3) has recently become important for dietary and pharmaceutical applications. The reported occurrence of y-linolenic acid in seed oils from plant families known to produce fatty acids, including 18:3 acids, with AS-cis and AS-trans double bonds makes it necessary to distinguish between Sc,9c,12c-, St,9c,12c-and 6~,9~,12~-octadecatrienoic acids by gas chromatography (CC) alone in routine screening operations. The separation of these acids using two different capillary GC systems has been investigated. The successful separation of octadecatrienoic acids with 5c, 5t and 6c double bonds is shown by way of gas chromatograms of the fatty acid methyl esters obtained from the seed oils of four different species of the family Ranunculaceae and of Xeranthemum and Pinus.

γ‐Linolenic acid containing oils have been found in seed lipids of a number of plants, but are restricted to certain genera and families,e.g., the Boraginaceae. Some of these oils have found considerable interest for pharmaceutical and dietary use,e.g., borage oil and evening primrose oil in treatment of essential fatty acid and Δ6 desaturase deficiency. Our investigation of the seed lipids of certain Mongolian and other Ranunculaceae has now shown the presnce of unusual fatty acids, including considerable amounts (up to 20%) ofγ‐linolenic acid in certain species ofAnemone, whereas this acid was found to be absent in other species ofAnemone. A number of other unusual fatty acids are present inA. rivularis but have not yet been identified. The significance of the presence ofγ‐linolenic acid, a Δ6 acid, is discussed in relation to δ5 fatty acids that had been reported to occur in the same plant family.

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