||Dr. Ilia J. Leitch, Prof. Andrew R. Leitch, Genome Size Diversity and Evolution in Land Plants, Plant Genome Diversity Volume 2, 2013, pp 307-322 p.308 right column 2nd paragraph
||Kenrick P, Crane PR (1997) The origin and early evolution of plants on land. Nature 389: 33–39 & Rensing SA, Lang D, Zimmer AD, Terry A, Salamov A et al (2008) The Physcomitrella genome reveals evolutionary insights into the conquest of land by plants. Science 319: 64–69PubMed ID18079367
||"Land plants first began to diverge around 450–460 million years ago (Mya) during the middle Ordovician (primary sources) and have since diversified
into four major groups: (1) the non-vascular bryophytes which comprise liverworts, mosses and hornworts, (2) the lycophytes, considered to be the first vascular plants to evolve and are sister to the remaining vascular plants
(3) the monilophytes comprising marattioid and leptosporangiate ferns, horsetails (Equisetum), whisk ferns
(Psilotum, Tmesipteris) and ophioglossoid ferns (e.g., Ophioglossum, Botrychium) and (4) the seed plants comprising angiosperms and gymnosperms." See Pannell 2017 PMID 28267976 p.R192 left column bottom paragraph: "The evolution of sexual reproduction constituted a major transition in the evolution of life, and occurred well before plants first ventured onto land some 470 million years ago." See Ishizaki 2017 PMID 27595342 p.73 left column 2nd paragraph: "The colonization of land by plants, which may have started as early as the Middle Ordovician period, approximately 470 Ma, resulted in the establishment of habitable environments on land, and thus promoted an enormous increase in the complexity of terrestrial ecosystems (ref 1)."