The study of pollen and spores, both living and fossil. Parts of these are highly resistant to decay, and provide evidence in palaeobotany from distant geological time. Palynology as a study of microfossils also looks at other parts of organisms which do not have reproductive function but which are physically preserved in a similar way in sediments, such as the chitin mouth parts of annelid worms. All these microfossils are called palynomorphs.
The part of a pollen grain or microspore that survives the geological process is made of a substance called sporopollenin, of unknown composition. As well as in the seeds of flowering plants and ferns (embryophytes) this is found in dinoflagellates (red tide algae) and acritarchs (uncertain affinity, perhaps some other kinds of algae).
Chitin is an animal compound very similar to the plant compound cellulose, and forms the scolecodonts or annelid mouth-parts, as well as the hard shells of many animals.
Palynology is useful in studying the climate and ecology of geological periods. The Greek word palyno means "sprinkle" and is related to "pollen".