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 capituliformisZhou, Zheng and Zhang, 2006 Yimaia qinghaiensisWu, 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 capituliformisZhou, Zheng and Zhang, 2006 Daohugou Bed, China, Callovian ^[2] Associated with leaves of Ginkgoites type
• Yimaia qinghaiensisWu, 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

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.