The term adopted by E. Schulze in 1891 to designate the plant cell components which are made soluble by dilute alkali or which go into solution quite readily in hot dilute mineral acids with the formation of simple sugars. Hemicelluloses constitute about one-fourth of perennial plants and about one-third of annual plants. The term is usually applied to those polysaccharides in the cell wall of land plants which are extractable by dilute alkaline solutions. The term has also been used to include all the polysaccharide components of the cell wall other than cellulose.