In 1682 appeared his great work on the "Anatomy of Plants", which also was largely a collection of previous publications. It was illustrated with eighty-two plates, with an appendix of seven papers mostly of a chemical character. The "Anatomy" is especially notable for its descriptions of plant structure. He described nearly all the key differences of morphology of stem and root, showed that the flowers of the Asteraceae are built of multiple units, and correctly said that stamens are male organs. "Anatomy of Plants" also contains the first known microscopic description of pollen.