Editing Spore (section)

===Spore tetrads and trilete spores===
{{Main|Evolutionary history of plants}}
Envelope-enclosed spore tetrads are taken as the earliest evidence of plant life on land,<ref name=Gray1985>{{cite journal
 | author = Gray, J.
 | year = 1985
 | title = The Microfossil Record of Early Land Plants: Advances in Understanding of Early Terrestrialization, 1970–1984
 | journal = [[Philosophical Transactions of the Royal Society B]]
 | volume = 309
 | issue = 1138
 | pages = 167–195
 | doi = 10.1098/rstb.1985.0077
 | last2 = Chaloner
 | first2 = W. G.
 | last3 = Westoll
 | first3 = T. S.
| jstor=2396358
 | bibcode=1985RSPTB.309..167G
| doi-access = free
 }}</ref> dating from the mid-Ordovician (early Llanvirn, ~{{Ma|470}}), a period from which no macrofossils have yet been recovered.<ref name=Wellman2000>{{cite journal
 | vauthors=Wellman CH, Gray J
 | year = 2000
 | title = The microfossil record of early land plants
 | journal = [[Philosophical Transactions of the Royal Society B]]
 | volume = 355
 | issue = 1398
 | pages = 717–732
 | doi = 10.1098/rstb.2000.0612
 | pmid = 10905606
 | pmc = 1692785
}}</ref>
Individual trilete spores resembling those of modern [[cryptogam]]ic plants first appeared in the fossil record at the end of the Ordovician period.<ref name="SteemansHerisse2009">{{cite journal|last1=Steemans|first1=P.|last2=Herisse|first2=A. L.|last3=Melvin|first3=J.|last4=Miller|first4=M. A.|last5=Paris|first5=F.|last6=Verniers|first6=J.|last7=Wellman|first7=C. H.|title=Origin and Radiation of the Earliest Vascular Land Plants|journal=Science|volume=324|issue=5925|year=2009|pages=353|issn=0036-8075|doi=10.1126/science.1169659|bibcode=2009Sci...324..353S|pmid=19372423|s2cid=206518080|url=https://biblio.ugent.be/publication/697223/file/709198.pdf|access-date=1 November 2017|archive-url=https://web.archive.org/web/20170922112350/https://biblio.ugent.be/publication/697223/file/709198.pdf|archive-date=22 September 2017|url-status=live|hdl=1854/LU-697223|hdl-access=free}}</ref>