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In this study we presented data on the production of branched root hairs in the seedlings of A. thaliana under progressive water deficit. The overall production of branched hairs was quite high under stress conditions and amounted to 8,27 %. On the contrary, this form of root hairs was almost absent in the control group (0,27 %). The highest number of branched hairs was produced at the beginning of the stress action. Branched root hairs are quite uniform structures in the sense of their morphology. To solve the question how the branched hairs grow, the structure of actin cytoskeleton was explored. This structure was different in the root hair and in its branch, which is an indication that the hair stops its growth at the moment when the branching starts. We have also characterized the production of branched root hairs in hormonal mutants of Arabidopsis and found the involvement of auxin in this process.