Ferns, lycophytes, mosses, liverworts and hornworts (the last three collectively termed bryophytes), along with various extinct lineages, represent a paraphyletic grade of spore-producing plants that appeared early in the fossil record of the terrestrialization of life. About 32,000 extant spore-producing plant species are known and several thousand extinct forms have been documented from the fossil record. Free-sporing plants played major roles in middle and late Paleozoic terrestrial ecosystems, and their fossil remains contributed to a large proportion of the world’s coal and gaseous hydrocarbon resources. Their relative importance, compared to seed plants has diminished since the Paleozoic except for intervals of resurgence after mass extinction events, and a phase of renewed diversification with the appearance of angiosperm-dominated closed forests in the Late Cretaceous and Cenozoic. Their complex and dynamic evolutionary history poses challenges for phylogenetic reconstruction, but also illustrates how this group evolved multiple strategies for arborescent growth, construction of leaves, heterospory, and the development of new lineages through genome duplications. Their long-term evolutionary success highlights their great adaptability in a changing world.