Formation of the hydrocyte system can be found very often in seed plants. In particular, during the formation of root shoots from adventicious buds in rootstock plants, in the case of natural coalescence of roots, and in different methods of shoot grafting. More strikingly it becomes apparent during regenerations; both in vitro an in vitro. The intensity of its development mainly depends on the organ's morphological nature, its functional loading and to an even lesser degree on the taxonomical affiliation. Detailed analyses of the hydrocyte system at light and electron microscopical levels show its complex histological structure. It includes water conductive elements (hydrocytes tracheids, rarely vessels members), phloem elements (sieve cells and sieve tube members with companion cells) and tracheidal parenchyma cells. The latter accomplish function of transferring, supporting, accumulation and storing of reserve substances. Therefore, the so-called hydrocyte system can be regarder as an original variety of the conductive system of seed plants.