[[File:Encephalartos sclavoi reproductive cone.jpg|thumb|upright|''[[Encephalartos sclavoi]]'' cone, about 30 cm long]]
Over 10001,000 living species of gymnosperm exist.<ref name="TPL" /> It was previously widely accepted that the gymnosperms originated in the [[Late Carboniferous]] period, replacing the [[Lycopodiophyta|lycopsid]] rainforests of the tropical region, but more recent phylogenetic evidence indicates that they diverged from the ancestors of [[Flowering plant|angiosperms]] during the [[Early Carboniferous]].<ref>{{Cite journal |last1=Li |first1=Hong-Tao |last2=Yi |first2=Ting-Shuang |last3=Gao |first3=Lian-Ming |last4=Ma |first4=Peng-Fei |last5=Zhang |first5=Ting |last6=Yang |first6=Jun-Bo |last7=Gitzendanner |first7=Matthew A. |last8=Fritsch |first8=Peter W. |last9=Cai |first9=Jie |last10=Luo |first10=Yang |last11=Wang |first11=Hong |date=May 2019 |title=Origin of angiosperms and the puzzle of the Jurassic gap |journal=Nature Plants |language=en |volume=5 |issue=5 |pages=461–470 |doi=10.1038/s41477-019-0421-0|pmid=31061536 |s2cid=146118264 }}</ref><ref>{{Cite journal |last1=Morris |first1=Jennifer L. |last2=Puttick |first2=Mark N. |last3=Clark |first3=James W. |last4=Edwards |first4=Dianne |last5=Kenrick |first5=Paul |last6=Pressel |first6=Silvia |last7=Wellman |first7=Charles H. |last8=Yang |first8=Ziheng |last9=Schneider |first9=Harald |last10=Donoghue |first10=Philip C. J. |date=2018-03-06 |title=The timescale of early land plant evolution |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=115 |issue=10 |pages=E2274–E2283 |doi=10.1073/pnas.1719588115 |pmc=5877938 |pmid=29463716|bibcode=2018PNAS..115E2274M |doi-access=free }}</ref> The radiation of gymnosperms during the late Carboniferous appears to have resulted from a whole [[Gene duplication|genome duplication]] event around {{ma|319}}.<ref name="Jiao2011">{{Cite journal |last1=Jiao |first1=Yuannian |last2=Wickett |first2=Norman J. |last3=Ayyampalayam |first3=Saravanaraj |last4=Chanderbali |first4=André S. |last5=Landherr |first5=Lena |last6=Ralph |first6=Paula E. |last7=Tomsho |first7=Lynn P. |last8=Hu |first8=Yi |last9=Liang |first9=Haiying |last10=Soltis |first10=Pamela S. |last11=Soltis |first11=Douglas E. |date=2011-04-10 |title=Ancestral polyploidy in seed plants and angiosperms |journal=Nature |volume=473 |issue=7345 |pages=97–100 |doi=10.1038/nature09916 |pmid=21478875 |bibcode=2011Natur.473...97J |s2cid=4313258 |author-link10=Pamela S. Soltis |author-link11=Douglas E. Soltis}}</ref> Early characteristics of seed plants are evident in fossil [[progymnosperms]] of the late [[Devonian]] period around 383 million years ago. It has been suggested that during the mid-Mesozoic era, pollination of some extinct groups of gymnosperms was by extinct species of [[Mecoptera|scorpionflies]] that had specialized [[proboscis]] for feeding on pollination drops. The scorpionflies likely engaged in pollination mutualisms with gymnosperms, long before the similar and independent coevolution of nectar-feeding insects on angiosperms.<ref>{{cite journal | last1 = Ollerton | first1 = J. | last2 = Coulthard | first2 = E. | year = 2009 | title = Evolution of Animal Pollination | journal = Science | volume = 326 | issue = 5954| pages = 808–809 | doi = 10.1126/science.1181154 | pmid = 19892970 | bibcode = 2009Sci...326..808O | s2cid = 856038 }}</ref><ref name="Ren">{{cite journal | last1 = Ren | first1 = D | last2 = Labandeira | first2 = CC | last3 = Santiago-Blay | first3 = JA | last4 = Rasnitsyn | first4 = A | last5 = Shih | first5 = CK | last6 = Bashkuev | first6 = A | last7 = Logan | first7 = MA | last8 = Hotton | first8 = CL | last9 = Dilcher | first9 = D. |display-authors=4 | year = 2009 | title = A Probable Pollination Mode Before Angiosperms: Eurasian, Long-Proboscid Scorpionflies | journal = Science | volume = 326 | issue = 5954| pages = 840–847 | doi = 10.1126/science.1178338 | pmid = 19892981 | pmc = 2944650 | bibcode = 2009Sci...326..840R }}</ref> Evidence has also been found that mid-Mesozoic gymnosperms were pollinated by [[Kalligrammatidae|Kalligrammatid lacewings]], a now-extinct family with members which (in an example of [[convergent evolution]]) resembled the modern butterflies that arose far later.<ref>{{cite journal | title=The evolutionary convergence of mid-Mesozoic lacewings and Cenozoic butterflies | journal = Proceedings of the Royal Society B: Biological Sciences | last1=Labandeira | first1=Conrad C. | last2=Yang | first2=Qiang | last3=Santiago-Blay | first3=Jorge A. | last4=Hotton | first4=Carol L. | last5=Monteiro | first5=Antónia | last6=Wang | first6=Yong-Jie | last7=Goreva | first7=Yulia | last8=Shih | first8=ChungKun | last9=Siljeström | first9=Sandra | last10=Rose | first10=Tim R. | last11=Dilcher | first11=David L. | last12=Ren | first12=Dong | volume = 283 | issue = 1824| doi=10.1098/rspb.2015.2893 | pages=20152893 | pmid=26842570 | pmc=4760178| year = 2016 }}</ref>
[[File:Zamia integrifolia02.jpg|thumb|''Zamia integrifolia,'' a cycad native to Florida]]
