With two varieties as materials, the meristem differentiation and the procedure of tobacco floral formation were investigated with an electronic microscope. The top flower was developed directly by the differentiation of the meristem. It first differentiated and flowered. The floral branches developed by vertically dividing the same meristem into two parts, one developing into a floral branch and the other remaining as the meristem. The process was repeated several times. This procedure was different from the monotonic process of most other floral differentiation. Because only one flower branch base was differentiated from the lateral base at one time, the floral branch was monotonic, not divergent or trifid. The nearer to the top, the earlier the branches differentiated. The closer to the top, the bigger the floral branch.