| Dipteronia | |
|---|---|
 | |
| Dipteronia sinensis, Berlin Botanical Gardens | |
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| Cluster of winged seeds ofDipteronia sinensis | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Sapindales |
| Family: | Sapindaceae |
| Subfamily: | Hippocastanoideae |
| Genus: | Dipteronia Oliv. |
| Species | |
Dipteronia is agenus with two living and one extinct species in the soapberry familySapindaceae. The living species are native to central and southern China. The fossil species has been found in MiddlePaleocene to EarlyOligocene sediments of North America and China.
Older classifications segregated themaples (Acer) andDipteronia into the familyAceraceae, however work by theAngiosperm Phylogeny Group (APG I onward) and related investigations[1] led to the subsuming of Acereae into Sapindaceae as the tribe Acereae.Dipteronia is considered to be the sister genus toAcer.[2]
They aredeciduous floweringshrubs or smalltrees, reaching 10–15 m (33–49 ft) tall. Theleaf arrangement is opposite andpinnate with between 7 - 15 leaflets on each leaf.[2] Theinflorescences are paniculate, terminal or axillary. Theflowers have fivesepals andpetals; staminate flowers have eightstamens, and bisexual flowers have a two-celledovary. Thefruit is a roundedsamara containing two compressed nutlets, flat, encircled by a broad wing which turns from light green to red with ripening.
The nameDipteronia stems from the Greek "di-" (two, both) & "pteron" (wings), from the winged fruits with wings on both sides of the seed.[citation needed]
There are only two living species,Dipteronia sinensis andDipteronia dyeriana; both are endemic to mainlandChina.[3]Dipteronia dyeriana is listed by the IUCN as being a "Red List" threatened species, and known from only five isolated populations in south-easternYunnan Province.[3]
The extinct speciesDipteronia brownii is known fromMiddle Paleocene toEarly Oligocene sites across western North America. The oldest fossils are found in theFort Union Formation of Wyoming and theTsagayan Formation of Northeastern coastal Russia.[4] In the Early Eocene the species expanded northward to theEocene Okanagan Highlands sites such as theKlondike Mountain Formation ofWashington,Driftwood Shales andTranquille Formation ofBritish Columbia as well as into theJohn Day Formation of central Oregon. During the middle to late Eocene the species spread east and south to theRuby Basin Flora of Montana and theFlorissant Formation of Colorado, while the last occurrences are in the Early Oligocene, Rupelian[5] of the Bridge Creek Flora in the upper John Day Formation.[2] Concurrently, severalDipteronia brownii fruits have also been collected fromRupelian32 ± 1 million years agolacustrinemudstones inChuxiong Yi Autonomous Prefecture southwesternChina.[6]
Media related toDipteronia at Wikimedia Commons