Lichenin, also known as lichenan or moss starch, is a complex glucan occurring in certain species of lichens.

[2] Chemically, lichenin is a mixed-linkage glucan, consisting of repeating glucose units linked by β-1,3 and β-1,4 glycosidic bonds.

[1] It is an important carbohydrate for reindeers and northern flying squirrels, which eat the lichen Bryoria fremontii.

It can be extracted by digesting Iceland moss in a cold, weak solution of carbonate of soda for some time, and then boiling.

By this process the lichenin is dissolved and on cooling separates as a colorless jelly.