Around 470 million years ago, plants transitioned from a freshwater ecosystem to colonise the land giving rise to a complex terrestrial ecosystem. Bryophytes, comprising liverworts, mosses, and hornworts, are the earliest diverging land plant lineage from flowering plants, and retain characters of the early land plant ancestors. During colonisation of land, plants evolved novel specialised metabolites, notably flavonoids, as they adapted to the additional abiotic and biotic stresses faced. Previous research has characterised stress-tolerance pathways that help liverworts and mosses cope with the land environment. However, limited information is available on stress tolerance capabilities of hornworts, at either the molecular or metabolic level. Our study aimed to characterise stress-induced-defence responses in hornworts. We exposed axenic cultures of Phaeoceros carolinianus to excess photosynthetically active light, nutrient starvation, cold and drought-like conditions and generated metabolite and transcriptomic data. The data confirmed absence of stress-induced flavonoids in hornworts, making them the only land plants to lack this biosynthetic pathway. However, there was differential regulation of phenolic and phytohormone (ethylene and abscisic acid) biosynthesis genes in response to stress. There was also accumulation of specific sulphur-containing metabolites in conjunction with differential expression of sulphur metabolism genes under cold and drought conditions.