A method of analyzing cell wall components based on a hot dilute acid extraction, followed by alcohol precipitation, of plant cellulosic materials such as cotton fibers or wood pulp. The extracts are analyzed by high pH anion exchange chromatography to separate and characterize the carbohydrates. This method extracts a characteristic series of carbohydrate multimers containing galactose, mannose and glucose. The pattern of multimers is indicative of origin of the cellulosic material (e.g., the plant species the material comes from) as well as quality and processing state of the material. The alcohol precipitation improves the discriminating powers of the analysis so that the species of origin of plant products can be identified.