The origin of plants and their colonization of land fundamentally transformed the terrestrial environment. Here we elucidate the basis of this formative episode in Earth history through patterns of lineage, gene and genome evolution. We use new fossil calibrations, a relative clade age calibration (informed by horizontal gene transfer) and new phylogenomic methods for mapping gene family origins. Distinct rooting strategies resolve tracheophytes (vascular plants) and bryophytes (non-vascular plants) as monophyletic sister groups that diverged during the Cambrian, 515–494 million years ago. The embryophyte stem is characterized by a burst of gene innovation, while bryophytes subsequently experienced an equally dramatic episode of reductive genome evolution in which they lost genes associated with the elaboration of vasculature and the stomatal complex. Overall, our analyses reveal that extant tracheophytes and bryophytes are both highly derived from a more complex ancestral land plant. Understanding the origin of land plants requires tracing character evolution across a diversity of modern lineages.

植物的起源及其在土地上的移殖从根本上改变了陆地环境。在这里，我们通过谱系、基因和基因组进化的模式阐明了地球历史上这一形成事件的基础。我们使用新的化石校准、相对进化枝年龄校准（通过水平基因转移获知）和新的系统发育学方法来绘制基因家族起源图。不同的生根策略将气管植物（维管植物）和苔藓植物（非维管植物）分解为在 515-4.94 亿年前的寒武纪期间分化的单系姐妹群。有胚植物茎的特征是基因创新的爆发，而苔藓植物随后经历了同样戏剧性的基因组还原进化事件，其中它们丢失了与脉管系统和气孔复合体的形成相关的基因。总的来说，我们的分析表明，现存的气管植物和苔藓植物都高度来源于更复杂的陆地植物祖先。了解陆生植物的起源需要追溯现代谱系多样性的特征进化。