Fig. 10

The process of trichome head senescence is shown. a Fully developed head with intact cuticle. No secretion of resin or shrinkage of the cuticle has occurred. Arrow points to the ring of secretory disc cells. b Shrinking of the cuticle and shriveling of the head has occurred, likely due to resin secretion. c, d Rupture of the cuticle (arrow) shows the dense granular appearance that is the resinous material underneath. e–f Shrinkage and collapse of the cuticle on mature glandular heads. The secretion of resin causes an aggregation of underlying resinous material and the surface of the head appears convoluted and wrinkled (arrows). g Close-up of dried resinous material. h, i Dried convoluted appearance of glandular heads that are completely senescent