In 1672 Nehemiah Grew had some idea that pollen was the means of fertilisation in higher plants. Using a microscope, he was the first to describe pollen in detail. This led to the discovery that all pollen grains in a species were alike. The study of pollen grains is called palynology. It is much used in micropaleontology. Sex in plants was discovered in 1694, when Rudolf Camerarius put his discovery into a letter.