''Yimaia'' is a extinct genus of Ginkgoalean tree, and the only member of the family Yimaiaceae. In botanical

form classification Form classification is the classification of organisms based on their morphology, which does not necessarily reflect their biological relationships. Form classification, generally restricted to palaeontology, reflects uncertainty; the goal of s ...

, its a

form taxon Form classification is the classification of organisms based on their morphology, which does not necessarily reflect their biological relationships. Form classification, generally restricted to palaeontology, reflects uncertainty; the goal of sc ...

for ginkgoalean

ovulate Ovulation is the release of eggs from the ovaries. In women, this event occurs when the ovarian follicles rupture and release the secondary oocyte ovarian cells. After ovulation, during the luteal phase, the egg will be available to be fertilized ...

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 ''Baiera'' is a genus of prehistoric gymnosperms in the order Ginkgoales. It is one of the oldest fossil foliage types of Ginkgoales, and is related to the genera ''Ginkgo'' and ''Ginkgoites''. Fossils of ''Baiera'' are found worldwide, and ha ...

'' or ''

Ginkgoites ''Ginkgoites'' is a genus that refers to extinct plants belonging to Ginkgoaceae. Fossils of these plants have been found around the globe during the Triassic, Jurassic, Cretaceous, with fossils also known from the Paleogene. The name was created ...

'' leaf morphospecies. Fossils have been found in

Middle Jurassic The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...

deposits in

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's most populous country, with a population exceeding 1.4 billion, slightly ahead of India. China spans the equivalent of five time zones and ...

Species

* ''Yimaia capituliformis'' Zhou, Zheng and Zhang, 2006

Daohugou Bed The Haifanggou Formation (), also known as the Jiulongshan Formation (), is a fossil-bearing rock deposit located near Daohugou () village of Ningcheng County, in Inner Mongolia, northeastern China. The formation consists of coarse conglomerates ...

, China,

Callovian In the geologic timescale, the Callovian is an age and stage in the Middle Jurassic, lasting between 166.1 ± 4.0 Ma (million years ago) and 163.5 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the ...

Associated with leaves of ''Ginkgoites'' type *''Yimaia qinghaiensis'' Wu, Yang and Zhou, 2006 Shimengou Formation,

Qinghai Qinghai (; alternately romanized as Tsinghai, Ch'inghai), also known as Kokonor, is a landlocked province in the northwest of the People's Republic of China. It is the fourth largest province of China by area and has the third smallest po ...

, China,

Associated with leaves of ''Baiera furcata'' type. * ''Yimaia recurva'' (type) Zhou et Zhang, 1988 Yima Formation,

Henan Henan (; or ; ; alternatively Honan) is a landlocked province of China, in the central part of the country. Henan is often referred to as Zhongyuan or Zhongzhou (), which literally means "central plain" or "midland", although the name is al ...

, China,

References

{{Taxonbar, from=Q2600332 Ginkgophyta