lignins

https://doi.org/10.1351/goldbook.L03528
@M03667@ constituents of wood related to @L03527@, composed of phenolic propylbenzene skeletal units, linked at various sites and apparently randomly.
Source:
PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1348 [Terms] [Paper]