Yimaia

Yimaia; Temporal range: Middle Jurassic PreꞒ Ꞓ O S D C P T J K Pg N
	Restoration of Yimaia recurva from the Jurassic of China
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Gymnospermae
Division:	Ginkgophyta
Class:	Ginkgoopsida
Order:	Ginkgoales
Family:	†Yimaiaceae; Zhou, 1997
Genus:	†Yimaia; Zhou et Zhang, 1988
Species
	Yimaia capituliformis Zhou, Zheng and Zhang, 2006; Yimaia qinghaiensis Wu, Yang and Zhou, 2006; Yimaia recurva (type) Zhou et Zhang, 1988;

Yimaia is an extinct genus of Ginkgoalean tree, and the only member of the family Yimaiaceae. In botanical form classification, its a form taxon for ginkgoalean ovulate organs. Yimaia species are distinguished from other Ginkgoales by the presence of "Ovulate organs consisting of a peduncle and up to eight or nine terminal, sessile, contiguous and orthotropous (straight, upright and with a micropyle at apex) ovules." The ovules are associated with leaves of either Baiera or Ginkgoites leaf morphospecies.^[1] Fossils have been found in Middle Jurassic deposits in China.

Species

Ginkgoites-type leaf associated with Yimaia capituliformis
Yimaia capituliformis Zhou, Zheng and Zhang, 2006 Daohugou Bed, China, Callovian^[2] Associated with leaves of Ginkgoites type
Yimaia qinghaiensis Wu, Yang and Zhou, 2006 Shimengou Formation, Qinghai, China, Middle Jurassic^[3] Associated with leaves of Baiera furcata type.
Yimaia recurva (type) Zhou et Zhang, 1988 Yima Formation, Henan, China, Middle Jurassic

References

^ Zhou, Zhi-Yan (March 2009). "An overview of fossil Ginkgoales". Palaeoworld. 18 (1): 1–22. doi:10.1016/j.palwor.2009.01.001.
^ Zhou, Zhiyan; Zheng, Shaolin; Zhang, Lijun (April 2007). "Morphology and age of Yimaia (Ginkgoales) from Daohugou Village, Ningcheng, Inner Mongolia, China". Cretaceous Research. 28 (2): 348–362. doi:10.1016/j.cretres.2006.05.004.
^ Wu, Xiangwu; Yang, Xiaoju; Zhou, Zhiyan (April 2006). "Ginkgoalean ovulate organs and seeds associated with Baiera furcata-type leaves from the Middle Jurassic of Qinghai Province, China". Review of Palaeobotany and Palynology. 138 (3–4): 209–225. doi:10.1016/j.revpalbo.2006.01.009.

[1] Zhou, Zhi-Yan (March 2009). "An overview of fossil Ginkgoales". Palaeoworld. 18 (1): 1–22. doi:10.1016/j.palwor.2009.01.001.

[2] Zhou, Zhiyan; Zheng, Shaolin; Zhang, Lijun (April 2007). "Morphology and age of Yimaia (Ginkgoales) from Daohugou Village, Ningcheng, Inner Mongolia, China". Cretaceous Research. 28 (2): 348–362. doi:10.1016/j.cretres.2006.05.004.

[3] Wu, Xiangwu; Yang, Xiaoju; Zhou, Zhiyan (April 2006). "Ginkgoalean ovulate organs and seeds associated with Baiera furcata-type leaves from the Middle Jurassic of Qinghai Province, China". Review of Palaeobotany and Palynology. 138 (3–4): 209–225. doi:10.1016/j.revpalbo.2006.01.009.

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