''Cyclocarya'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (). The term angiosperm is derived from the Ancient Greek, Greek words (; 'container, vessel') and (; 'seed'), meaning that the seeds are enclosed with ...

s in the family

Juglandaceae The Juglandaceae are a plant family known as the walnut family. They are trees, or sometimes shrubs, in the order Fagales. Members of this family are native to the Americas, Eurasia, and Southeast Asia. The nine or ten genera in the family have ...

, comprising a single species ''Cyclocarya paliurus'' (qing qian liu or wheel wingnut), formerly treated in the genus ''

Pterocarya ''Pterocarya'', often called wingnuts in English, are trees in the walnut family Juglandaceae. They are native to Asia. The botanic name is from Ancient Greek (''pteron'') "wing" + (''karyon'') "Nut (fruit), nut". Description ''Pterocarya'' a ...

'' as ''Pterocarya paliurus''. It is native to eastern and central

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 ...

.Flora of China
''Cyclocarya''
/ref>Flora of China
''Cyclocarya paliurus''
/ref> It is a

deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, e.g., including only woody plants with secondary growth, only ...

growing to 30 m tall. The foliage is similar to ''Pterocarya'', with pinnate

leaves A leaf (: leaves) is a principal appendage of the stem of a vascular plant, usually borne laterally above ground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, stem, ...

20–25 cm long with five to eleven leaflets, the terminal leaflet present; the leaflets are 5–14 cm long and 2–6 cm broad. The

flower Flowers, also known as blooms and blossoms, are the reproductive structures of flowering plants ( angiosperms). Typically, they are structured in four circular levels, called whorls, around the end of a stalk. These whorls include: calyx, m ...

s are

catkin A catkin or ament is a slim, cylindrical flower cluster (a spike), with inconspicuous or no petals, usually wind- pollinated ( anemophilous) but sometimes insect-pollinated (as in '' Salix''). It contains many, usually unisexual flowers, arra ...

s; the male (pollen) catkins are produced in clusters (not singly as in ''Pterocarya''), the female catkins 25–30 cm long at maturity, bearing several small winged nuts with a circular wing 2.5–6 cm diameter right round the nut (instead of two wings at the sides as in ''Pterocarya'').

Fossil record

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

endocarp Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits. Fruitlike structures may develop directly from the seed itself rather th ...

s of †''Cyclocarya nemejcii'' from the early

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

, have been found in the Kristina Mine at

Hrádek nad Nisou Hrádek nad Nisou (; , ) is a town in Liberec District in the Liberec Region of the Czech Republic. It has about 8,000 inhabitants. The historic town centre is well preserved and is protected as an urban monument zone. Administrative division Hr� ...

in North Bohemia, the

Czech Republic The Czech Republic, also known as Czechia, and historically known as Bohemia, is a landlocked country in Central Europe. The country is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the south ...

. Described first from the

Middle Miocene The Middle Miocene is a sub-epoch of the Miocene epoch (geology), epoch made up of two Stage (stratigraphy), stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene. The sub-epoch lasted from 15.97 ± 0. ...

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

†''Cyclocarya ezoana'' is also known from the

Seldovia Point Flora of

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

. 10 Ma old

leaflets that are very similar to it have been found in Tröllatunga-Gautshamar Formation in

Iceland Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...

. The Icelandic fossils and †''C. ezoana'' are similar to †''C. cyclocarpa'' from the

Early Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to ...

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

.Late Cainozoic Floras of Iceland: 15 Million Years of Vegetation and Climate History in the Northern North Atlantic by Thomas Denk, Friðgeir Grimsson, Reinhard Zetter and Leifur A. Símonarson - Springer Science & Business Media, 28. mar. 2011 - 854 pages

Gallery

Cyclocarya paliurus IMG 2983.jpg, ''Cyclocarya paliurus'' in the Dresden Botanical Garden Cyclocarya paliurus seeds, by Omar Hoftun.jpg, Winged nutlets

References

Juglandinae Monotypic Fagales genera Flora of China {{Fagales-stub