Xyloglucan is a polysaccharide found in the primary cell walls of all higher plants examined. Its cellulose-like backbone, which is about 0.15 to 1.5 μm long, consists of 300 to 3 000 β-(1→4)-linked D-glucopyranose residues. About 60–75% (or, in grasses, about 30–40%) of the glucose residues have side-chains attached to position 6. The major side-chains are: D-xylopyranosyl-α-1 -→, D-galactopyranosyl-β-(1 →2)-D-xylopyranosyl-α-I→ , L-arabinofuranosyl-(1 -→2)-D-xylopyranosyl-α-1 -→, and (except in grasses) L.-fucopyranosyl-α-(1 -→2)-D-galactopyranosyl-β-(1-→2)-D-xylopyranosyl-α-1 -→. There is some regularity in the distribution of these side-chains along the backbone.