1) The dorsiventrality of the assimilatory organs in some conifers can be induced by the external light condition and the structure of the growing region can be inverted with ease by the inversion of light incident to the shoot surface. Two types of assimilatory organs with induced dorsiventrality are distinguished among them: the Thujopsis type and the Podocarpus imbricala type. 2) Thujopsis type. The assimilatory organ has a cupressoid form. The shoots branch horizontally in one plane and have upper and lower pairs of decussate leaves concrescent to the stem axis; the lateral pairs compressed in the direction perpendicular to the stem axis. Palisade parenchyma are restricted to the upper surface of the shoot. In Thujopsis dolabrata Sieb, et. Zucc. and Libocedrus arfakensis L. S. Gibbs. stomata are distributed only on the lower surface of the shoots. In Chamaecyparisobtusa End1. and Libocedrus decurrens Torr. no dorsiventrality is found in the distribution of stomata. They are confined to the narrow adaxial surface of all leaves and to the portion of the upper and lower leaves which is overlapped by the lateral leaves. 3) Podocarpus imbricata type. Leaves, developed in spiral phyllotaxis at the stem apex, are arranged in one plane by subsequent growth. In spite of the information made by Goebel no dorsiventrality in the structure was observed in the material available to the present author. 4) Seedling of Phyllocladus protractus Pilger has small pennate leaves with normal dorsiventral structure. The phyllocladium developed on its seedling is definitely dorsiventral, stomata are confined to the lower surface and assimilatory cells of the upper side are more elongated than those of the lower side. The palisade cells disappear completely on the lower side of phyllocladium developed at a later stage. In Phyllocladus rhomboidalis Rich. assimilatory cells are found on both sides in phyllocladium developed on adult plant. The dorsiventrality of these phyllocladium may probably be induced by external light condition as is the case in the other two types.