The aliphatic components of the polymeric lipid of the bundle sheaths of the leaves of Zea mays were analyzed by combined gas-liquid chromatography and mass spectrometry. The major components were 7,16-, 8,16-, 9,16- and 10,16-dihydroxyhexadecanoic acid, 18-hydroxyoctadecenoic acid, octadecene-1,18-dioic acid, epoxy and trihydroxy C18 acids and long chain acids and alcohols. The composition of this 'suberin type' polymer is compared with that of the cuticular polymer of the leaf. © 1979.