Abstract: The present paper deals with experiments on the development of adventive embryos of Hosta caerulea by the application of 0.1% IAA, and 0.01% IAA, and 0.01% 2,4-D to the pistils of emasculated flowers. The results are summarized below. 1. When IAA or 2,4-D was employed to substitute pollination, 80%–90% of ovaries remained attached to the plant and continued to grow for a time. All the controls withered and fell off within 3 days. 2. In hormone-treated ovules, the unfertilized egg and secondary nucleus failed to develope, so that there was neither zygote embryo nor endosperm, but the initiating cells of adventive embryos divided to form young adventive embryos. 3. In the hormone-treated ovules, in the early stages, the growth condition and growth rate of adventive embryos were similar to those of pollinated plants. In later stages the former were characterized by the formation of callus-like cell groups and lack of cell differentiation. About 24 days later the ovules showed progressive shrinkage accompanied by a cessation of growth of the adventive embryos. 4. According to the facts observed the conclusion may be drawn that there is no direct relationship between pollination and the origination of adventive embryo, but in further differentiation of the embryo the presence of endosperm or growth-promoting and growth-regulating substances produced by it are necessary.