Abstract: Paraffin sections of Pulsatilla koreana petiole explants were studied to illustrate the microstructure of the meristematic nodule and plant regeneration pathway. Meristematic nodules could be induced from petiole explants on Murashige and Skoog medium containing 3 mg⋅L^–1 zeatin with 0.5 mg⋅L^–1 indole acetic acid. After 42 days of culture the frequency of nodule induction was 82.5%, and 95% of nodules converted to adventitious shoots after 56 days culture. Globular structures were observed after 14 days’ induction. Prenodular structures of cambial origin appeared from the calluses and gave rise to nodules; shoot buds formed after 28 days’ of culture. Nodules kept giving rise to sub-nodules, from which arose an increasing number of shoot buds. Most apical meristem structures with leaf primordia were observed after 42 days’ culture. Meristemoid regions and cells were much smaller in callus-like tissue than in surrounding cells. Some parts of the sections showed epidermal or sub-epidermal cells, vascular cambium, and meristemoid cells, which were regularly or irregularly distributed on the callus-like tissue. These structures provide evidence that callus-like tissue plays an important role in Pulsatilla species for shoot or root differentiation.