Editing Apomixis (section)

==Evolution==
Because apomictic plants are genetically identical from one generation to the next, each lineage has some of the characters of a true [[species]], maintaining distinctions from other apomictic lineages within the same [[genus]], while having much smaller differences than is normal between species of most genera. They are therefore often called [[microspecies]]. In some genera, it is possible to identify and name hundreds or even thousands of microspecies, which may be grouped together as [[species aggregate]]s, typically listed in [[Flora (publication)|flora]]s with the convention "''Genus species'' agg." (such as the [[bramble]], ''Rubus fruticosus'' agg.). In some [[Family (biology)|plant families]], genera with apomixis are quite common, for example in [[Asteraceae]], [[Poaceae]], and [[Rosaceae]]. Examples of apomixis can be found in the genera ''[[Crataegus]]'' (hawthorns), ''[[Amelanchier]]'' (shadbush), ''[[Sorbus]]'' ([[rowan]]s and [[whitebeam]]s), ''[[Rubus]]'' (brambles or blackberries), ''[[Poa]]'' (meadow grasses),  ''[[Nardus stricta]]'' (matgrass), ''[[Hieracium]]'' (hawkweeds) and ''[[Taraxacum]]'' (dandelions).  Apomixis is reported to occur in about 10% of globally extant [[fern]]s.<ref name=Liu>{{cite journal | last1=Liu | first1=Hong-Mei | last2=Dyer | first2=Robert J. | last3=Guo | first3=Zhi-You | last4=Meng | first4=Zhen | last5=Li | first5=Jian-Hui | last6=Schneider | first6=Harald | title=The Evolutionary Dynamics of Apomixis in Ferns: A Case Study from Polystichoid Ferns | journal=Journal of Botany | volume=2012 | date=2012-11-05 | issn=2090-0120 | doi=10.1155/2012/510478 | pages=1–11 | doi-access=free }}</ref>  Among [[Polystichum|polystichoid]] ferns, apomixis evolved several times independently in three different [[clade]]s.<ref name=Liu />

Although the [[evolution]]ary advantages of [[sexual reproduction]] are lost, apomixis can pass along traits fortuitous for evolutionary fitness. As [[Jens Clausen]] put it:<ref>{{cite journal|last= Clausen| first= J.|year=1954|title=Partial apomixis as an equilibrium system|journal=Caryologia|volume=1954, Supplement|pages=469–479}}</ref>{{rp|470}}<blockquote>The apomicts actually have discovered the effectiveness of mass production long before Mr.&nbsp;[[Henry Ford]] applied it to the production of the automobile. ... Facultative apomixis ... does not prevent variation; rather, it multiplies certain varietal products.</blockquote>

'''Facultative apomixis''' means that apomixis does not always occur, i.e., sexual reproduction can also happen. It appears likely that all apomixis in plants is facultative;<ref name=Savidan>{{cite book|author=Savidan, Y.H.|year=2000|title=Plant Breeding Reviews|chapter=Apomixis: genetics and breeding|volume=18|pages=13–86|doi=10.1002/9780470650158.ch2|isbn=9780470650158}}</ref><ref name=Hojsgaard2022>{{Cite Q|Q115563996|doi-access=free}}</ref> in other words, that "obligate apomixis" is an artifact of insufficient observation (missing uncommon sexual reproduction).