Abstract: Phlox Drummondii Hook, is an important and famous horticulture plant. In the experi-ments, embryoids were obtained when leaf explants of P.drummondii Hook were cultured on MS solid medium supplemented with 0.1 mg / L NAA and 2 mg / L 6-BA. The cultured materials were fixed with Carnoy's fluid and prepared for paraffin sections, and stained with iron alum haematoxylin. There were two ways in the embryogenesis: One is that the differentiated cells of leaf explants with certain function dedifferentiated into embryonic cells, e.g. leaf epidermal cells, mesophyll cells, boundle sheath cells and phloem parenchyma cells were all able to do it. The other is that, at first, leaf explants dedifferentiated into calli and formed many meristem centers, and then vascular systems occurred near them, and in the end, embryonic cells or meristem cell masses were produced around them. The embryonic cells formed through these two ways possesed a developmental process similar to general zygotic embryoes with the proembryos of 2~ 4 cells, ball and the embryoids of heart, torpedo or with cotyledons. The embryoid with double polarities finally developed further into the intact plantlet.

Key words: Phlox drummondii