Pollen grains are the earliest reliable and recognizable remains of the flowering plants yet found. They occur in deposits dating back to the end of the Jurassic period and as their detailed structure is often so well preserved, the pollen grains may be identified to many species of tree, grass and herb. Their structures have been utilized by botanists in studies of evolution and of taxonomy, while geologists have used their presence for making stratigraphical correlations. Pollen analysis has largely been concerned with the identification and counting of pollen grains in Quaternary deposits. Increasing use is being made of quantitative pollen spectra in providing evidence for climatic change and vegetational history, and in the study of the interrelationships between man, soil, climate and vegetation. Pollen analysis will continue to be one of the basic tools in detailed analysis of deposits containing organic remains.