Within the wide diversity of plant species on earth, a main distinction is made into vascular and non-vascular plants. However, the presence of conductive tissues is not a simple binary trait, as some non-vascular mosses do have conductive tissues which can be compared to those of vascular plants at the molecular level. We however have very little information on the molecular basis of the transition from non-vascular to vascular plants. Unfortunately, the existing model species for molecular biological applications (P. patens and M. polymorpha) do not contain functionally homologous tissues for all cell types found in vascular plants; hampering research into vascular development and evolution. In this research project, we propose to establish the moss Atrichum angustatum as ideal model system to study vascular development and evolution at molecular level by i) assembling and annotating the genome; ii) developing protocols for propagation, transformation and a basic molecular biology toolbox; iii) generating and validating high resolution spatiotemporal transcriptome information; and iv) developing an on-line platform to make all this information searchable and publicly available. The outcomes of this research proposal will not only provide novel insights into the evolution of vascular tissues and acquisition of specific vascular cell identities; but will at the same time generate important resources to the broader plant evo-devo community.