''Yimaia'' is an 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 sc ...

, its a

form taxon Form classification is the classification of organisms based on their morphology (biology), morphology, which does not necessarily reflect their biological relationships. Form classification, generally restricted to palaeontology, reflects uncer ...

for ginkgoalean

ovulate Ovulation is an important part of the menstrual cycle in female vertebrates where the egg cells are released from the ovaries as part of the ovarian cycle. In female humans ovulation typically occurs near the midpoint in the menstrual cycle and ...

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 of 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 as a form g ...

'' leaf morphospecies. Fossils have been found in

Middle Jurassic The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 161.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relativel ...

deposits in

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

Species

''Yimaia capituliformis'' Zhou, Zheng and Zhang, 2006 Daohugou Bed, China,

Callovian In the geologic timescale, the Callovian is an age and stage in the Middle Jurassic, lasting between 165.3 ± 1.1 Ma (million years ago) and 161.5 ± 1.0 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 is an inland Provinces of China, province in Northwestern China. It is the largest provinces of China, province of China (excluding autonomous regions) by area and has the third smallest population. Its capital and largest city is Xin ...

, China,

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

Henan Henan; alternatively Honan is a province in Central China. Henan is home to many heritage sites, including Yinxu, the ruins of the final capital of the Shang dynasty () and the Shaolin Temple. Four of the historical capitals of China, Lu ...

, China,

References

{{Taxonbar, from=Q2600332 Ginkgophyta