Xylose. Polarised light micrograph of crystals of wood sugar, known as xylose (D-xylose). It is of use to diabetics. The chemical formula is C5. H10. O5; melting point is 144 degrees Celsius. Xylose is a pentose sugar widely distributed in plants. It is found especially in wood such as cherry or maple, in straw, and seed husks. It is not found in a free state but in the form of xylan, a polysaccharide made up of D-xylose units and occurring in association with cellulose. It also occurs as part of glycosides and is not a fermentable sugar. Xylose is used as a diabetic food and industrially in dyeing and tanning. Magnification: x12 at 35mm size.