Abstract: In this anatomical study on vascular tissue of Rumex crispus var. unicallosus, authors found four types of vascular cylinder, from the root apex to the shoot apex, existing in the seedling of this plant:i. e. the type of actinostele which is triarch in the root; the type of haplostele in the lower part of cotyledon node zone; the type of siphonostele in the upper part of cotyledon node zone and the type of eustele in epicotyl-shoot zone. This result seems to support the CNZ theory proposed in 1990,because the haplostele, which is considered the most primitive type of vasular cylinder,exists in cotyledon node zone and there is a discussion about it here of. But the existence of siphonostele indicates a difference between CNZ theory and the conclusion done in this paper, and therefore the authors think it should be a problem deserving of some further study

Key words: Rumex crispus var. unicallosus, Root-stem transforming zone, CNZ theory