Palynomorphs are broadly defined as organic-walled microfossils between 5 and 500 micrometres in size. They are extracted from sedimentary rocks and sediment cores both physically, by ultrasonic treatment and wet sieving, and chemically, by chemical digestion to remove the non-organic fraction. Palynomorphs may be composed of organic material such as chitin, pseudochitin and sporopollenin. Palynomorphs that have a taxonomy description are sometimes referred to as palynotaxa.