View source for Biology:Yunia

{{Short description|Extinct genus of spore-bearing plants}}
{{Automatic taxobox
| fossil_range = {{Geological range/linked|Early Devonian}}
| image = Yunia dichotoma reconstruccion.jpg
| image_upright = 0.7
| image_caption = Reconstruction of ''Yunia dichotoma'' according to its description.
| taxon = Yunia
| authority = S.G.Hao & C.B.Beck (1991)<ref name="HaoBeck1991"/>
| display_parents = 7
| type_species = '''''Yunia dichotoma'''''
| type_species_authority = S.G.Hao & C.B.Beck (1991)
| subdivision_ranks = Species
| subdivision = 
* †''Y.  dichotoma'' <small>S.G.Hao & C.B.Beck (1991)</small>
* †''Y.  guangnania'' <small>S.G.Hao & Xue (2013)</small>
}}

'''''Yunia''''' is a [[Biology:Genus|genus]] of extinct [[Biology:Vascular plant|vascular plant]]s from the [[Earth:Early Devonian|Early Devonian]] (Pragian or Siegenian stage, around {{Period span/brief|Pragian}}). It was first described from the Posongchong Formation of Yunnan, China. The leafless plant consisted of spiny stems, some 2 to 5&nbsp;cm wide, which branched dichotomously at wide angles in a cruciate arrangement. Each stem contained [[Biology:Vascular tissue|vascular tissue]] with one or two strands of [[Biology:Xylem#Primary and secondary xylem|protoxylem]]. The spore-forming organs ([[Biology:Sporangium|sporangia]]) were elongated and borne on short stalks. The spores had a  relatively smooth sculptural pattern and were trilete (i.e. each spore has three lines on it resulting from its formation in a tetrahedral set of four spores).<ref name="HaoBeck1991">{{Citation |last1=Hao |first1=Shou-Gang |last2=Beck |first2=Charles B. |year=1991 |title=''Yunia dichotoma'', a Lower Devonian plant from Yunnan, China |journal=Review of Palaeobotany and Palynology |volume=68 |issue=3–4 |pages=181–195 |doi=10.1016/0034-6667(91)90022-U |hdl=2027.42/29227 |name-list-style=amp |url=https://deepblue.lib.umich.edu/bitstream/2027.42/29227/1/0000282.pdf |hdl-access=free }}</ref><ref>{{Citation |last1=Taylor |first1=T.N. |last2=Taylor |first2=E.L. |last3=Krings |first3=M. |year=2009 |title=Paleobotany : The Biology and Evolution of Fossil Plants |edition=2nd |location=Amsterdam; Boston |publisher=Academic Press |isbn=978-0-12-373972-8 |name-list-style=amp }}, p. 262</ref>

In 2004, Crane et al. published a simplified [[Biology:Cladogram|cladogram]] for the [[Biology:Polysporangiophyte|polysporangiophyte]]s in which ''Yunia'' is basal to the [[Biology:Lycopodiophyta|lycophytes]] (clubmosses and relatives).<ref>{{Citation |last1=Crane |first1=P.R. |last2=Herendeen |first2=P. |last3=Friis |first3=E.M. |year=2004 |title=Fossils and plant phylogeny |journal=American Journal of Botany |volume=91 |pages=1683–99 |doi=10.3732/ajb.91.10.1683 |issue=10 |pmid=21652317|doi-access=free }}</ref> It had previously been placed in the "trimerophytes"<ref name="HaoBeck1991"/> (a group now thought to be paraphyletic), which were considered to have given rise to all the other vascular plants ''except'' the lycophytes.<ref>{{Harvnb|Taylor|Taylor|Krings|2009|p=259ff.}}</ref>
{{clade
|  label1=tracheophytes
}}
Hao and Xue in 2013 considered the genus as a questionable zosterophyll.<ref name=HaoXue13/>

==References==
{{Reflist|refs=
<ref name=HaoXue13>{{Citation |last1=Hao |first1=Shougang |last2=Xue |first2=Jinzhuang |date=2013 |title=The early Devonian Posongchong flora of Yunnan: a contribution to an understanding of the evolution and early diversification of vascular plants |location=Beijing |publisher=Science Press |isbn=978-7-03-036616-0 |url=https://www.researchgate.net/publication/269875285 |access-date=2019-10-25 |page=52 |name-list-style=amp }}</ref>
}}

==External links==
* [https://archive.today/20121204162818/http://www.amjbot.org/content/vol91/issue10/images/large/abot-91-10-04-f01.jpeg Cladogram] from {{Harvnb|Crane|Herendeen|Friis|2004}}

{{Taxonbar|from=Q8061285}}

[[Category:Early Devonian plants]]
[[Category:Zosterophylls]]

{{Sourceattribution|Yunia}}