Hornworts have an array of unique features that can help illuminate not only the early evolution of land plants, but also the alternative paths for nitrogen and carbon assimilation (respectively via cyanobacterial symbiosis and a CO2-concentrating mechanism). Despite this, hornworts are also one of the few plant lineages having only limited genomic and genetic resources available. To address this issue, first we have assembled eight new chromosome-level genomes from across the hornwort phylogeny, covering all the families and most of the genera. Importantly, these genomes represent a diverse trait combination—including presence/absence of pyrenoids, stomata, and sex chromosomes—and will form the basis for future comparative studies. Furthermore, a biolistic-mediated transformation has been developed that can efficiently introduce genetic elements into the model hornwort Anthoceros agrestis, as well as a few other species. Building upon these new resources and tools, we are investigating the genetics of hornworts’ CO2-concentrating mechanism, and our findings will be presented here. We anticipate that enabling genetic research in hornworts will not only complement the other two bryophyte models (the moss Physcomitrium patens and the liverwort Marchantia polymorpha), but will also bring unprecedented opportunities to study a distinct plant with unparalleled biological properties.