The degree of polylamellation in the fibre cell walls of the bamboo Phyllostachys virideglaucescens has been investigated. The extent of polylamellation was found to be influenced by position of the vascular bundle in the culm wall, in certain positions by age of the culm and, most strikingly, with position within the vascular bundle. The number of wall lamellae was variable but tended to be greatest in fibres adjacent to either vascular elements or ground tissue at the periphery of the fibre bundles. A similar pattern of variation in fibre wall lamellation was also observed in two other species of bamboo. The characteristic pattern of fibre wall lamellation probably influences mechanical properties and warrants further investigation.