Internode elongation in lily (Lilium longiflorum Thunb.) increased significantly in the uppermost internodes during the development of the flowers. The last 4 internodes contributed as much to plant height as the first 30 internodes. Removal of the flowers reduced internode elongation, and within the range of 1–4 flowers per plant, length of the uppermost internodes was directly related to flower number. Removal of the perianth of the flowers was almost as effective as defloration in reducing internode growth. Application of gibberellic acid to decapitated stems completely replaced the effect of the flowers, whereas indoleacetic acid was only partially effective in restoring internode growth.