"), Jeffrey G. Duckett3 and Martin I. Bidartondola 'Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK; 2Jodrell Laboratory. Royal Botanic Gardens, ICew,TW9 3DS, UK; 3 Department of Life Sciences, Plants Division, Natural History Museum, Cromwell Road, London, SW7 5BD, UK ("Author for corresp