Palynology — pollen morphology, stratigraphic diagrams, and vegetation reconstruction
Pollen grains are preserved for millennia in peat bogs, lake sediments, and cave deposits because their outer wall (exine) is composed of sporopollenin — one of the most chemically resistant biological polymers known. Each plant family produces morphologically distinctive pollen grains identifiable by size, shape, aperture number (colpi and pores), and surface sculpture. Palynologists count hundreds of grains per sample and express taxa as percentages of the total pollen sum. Stratigraphic diagrams show how vegetation assemblages changed through time, recording forest clearances, climate shifts, and the arrival of agriculture (evidenced by cereal pollen and Plantago lanceolata, a weedy companion of farmers).