Because pollen grains are so tiny, less than a teaspoonful of sediment can contain many thousands of them. Most pollen grains are extremely resistant to decay and are preserved in large numbers in many types of sediments. Pollen grains have distinct shapes and surface patterns that allow palynologists to identify them according to the plants that produced them. The walls of pollen grains are made from sporopollenin, one of the most resistant natural chemical substances known. This explains why the grains preserve so well and are still found relatively intact and identifiable after thousands or millions of years burial.
Many grains are quite beautiful, with intricate textures and shapes.
One of the great pleasures of palynology, and a source of constant wonder, is looking at all these tiny but perfectly-formed grains under the microscope. A small amount of lake mud may contain pollen grains from up to thirty to fifty different types of plants. Palynologists assume that these plants had the same climatic and ecological tolerances as their modern descendants. They can use this information, therefore, to reconstruct past climate and landscape conditions. Quaternary palynologists usually work on a core of lake mud or peat, or sometimes cores from the sea-bed.