The initiation of floral organs, especially that of petal primordia was observed by a scanning electron microscope in cabbage, Chinese kale, kohlrabi, kale, hong-tsai-tai, pakchoi, tsai-shin and Japanese radish. 1. Seven floral stages could be discerned in cultivars in every species : the vegetative stage; the dome-forming stage; the flower bud-forming stage; the sepal-forming stage; the stamen and pistil-forming stage; the early petal-elongation stage, and late petal-elongation stage. 2. Petals and outer stamens of tsai-shin were formed earlier followed by the initiation of inner stamens. In other cultivars, the petals and stamens were initiated almost simultaneously. 3. Petal primordia were smaller than those of other floral primordia and their development stopped soon after initiation. The elongation of petal was delayed, compared with that of stamens and pistil. 4. These observations confirm the normal sequence of sepal initiation followed by those of petals, stamens, and pistil in all eight cruciferous vegetables studied.
