When plants colonized the land evolved specialized structures which enabled anchorage and movement of nutrients and water throughout the whole plant, the root and the vascular system. Large evolutionary changes such as this are the result of modifications of the gene regulatory network (GRN), composed of regulators controlling the expression of target genes, that controls organ development. In order to unravel the key changes which led to the evolution of vascular tissue, I will use comparative network biology and Single Cell technologies (scRNA-, scATAC-Seq) to obtain a detailed overview of the regulatory networks in different cell-types of three plant species, including non-vascular and vascular plants. By following the changes of the cell-type specific sub-networks in the different species, I will identify conservation and differences in network organization which can eventually explain morphological evolution. While the use of distantly related species will offer the possibility to unravel master regulators and new molecular players which contributed to the transition from non-vascular to vascular plants, the comprehensive datasets will provide an important resource for the whole plant community to study both gene expression and regulation at single cellular level.