The plant surface of sunflower is covered with at least three types of trichomes, two of which have glandular nature and produce a rich spectrum of allelochemicals. While the development and metabolic activity of the biseriate multicelluar glands has been investigated intensively in the past, hardly any information was yet available on the uniseriate linear glands. The current study of this latter type of plant hairs provides first detailed results on: (i) the occurrence in Helianthus and related genera, (ii) the accumulation of sesquiterpenes and other metabolites, and (iii) a possible a function of the trichomes in plant insect interaction.