False-colour scanning electron micrograph (SEM) of two pollen grains of cocksfoot grass, Dactylis glomerata. The pit on the right-hand grain is the germination pore, out which the pollen tube grows. Cocksfoot pollen is a wind- dispersed summer pollen & a major cause of hay fever (Allergic rhinitis or pollenosis). Sufferers produce a sensitising antibody, immunoglobin E (IgE), which attaches to cells in the nose & eyes. It reacts with inhaled pollen, causing the release of various chemicals including histamine. Histamine causes the mucous membranes of the nose, eyes & throat to swell & become inflamed, bringing on the symptoms of hay fever. Magnification: x370 at 35mm size. Gold tint. Original is bw print B786/073 Ref: MICROCOSMOS, fig. 4.32, p. 82