1. Comparative studies, the number, form and pattern of ramification, on the petiole stele types of 3 orders, 11 families, 41 genera and 104 species of ferns found in Korea were carried out. 2. The number, form and pattern of the ramified steles were found to be different according to the taxa studied. 3. The stele types of petiole may be classified as unibranch, bibranch, tribranch, and polybranch. The species belonging to each stele type were found to have similar embyrological characteristics among them. Therefore, it might be reasonable to assume that the stele type can be used as a basis for classifing family lines. 4. The number of ramified steles in the petiole were found to be in general agreement with that of the leaf traces, though a few exceptional cases were found. 5. It is well known that there is a large degree of disgreement among the taxanomists on the classification of ferns. The classification of ferns by means of petiole stele types may ease this difficulty in certain extent.