Chowdhury and Tandan1 report that, in certain Indian woody species, radial growth does not commence until the first period of extension growth has ceased, and they contrast this behaviour with that in European and North American species, where both extension and radial growth normally proceed simultaneously, and in which an obligate dependence of radial on extension growth is generally held2 to occur in both diffuse-porous and ring-porous types. The results of recent experiments of mine, however, indicate that some modification of this generally accepted view is necessary so far as the initiation of radial growth in ring-porous European species is concerned.