| Elaeagnaceae | |
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Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Rosales |
| Family: | Elaeagnaceae Juss. 1789[1] |
| Type genus | |
| Elaeagnus L., 1753 | |
| Genera | |
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| Synonyms[1] | |
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TheElaeagnaceae are a plantfamily, theoleaster family, of the orderRosales comprising smalltrees andshrubs, native to temperate regions of the Northern Hemisphere, south into tropical Asia and Australia. The family has about 60 species in three genera.[2]
They are commonlythorny, with simpleleaves often coated with tiny scales or hairs. Most of the species arexerophytes (found in dryhabitats); several are alsohalophytes, tolerating high levels ofsoil salinity.
The Elaeagnaceae often harbor nitrogen-fixing actinomycetes of the genusFrankia inroot nodules, making them useful for soil reclamation.[3] This characteristic, together with their production of plentiful seeds, often results in the Elaeagnaceae being regarded as weeds.
The stems and leaves are covered with silvery brown or golden hairs which are eitherpeltate or scaly.Shepherdia andHippophae are unisexual, the female and male borne on different plants (dioecious). There are no petals, theperianth comprising a single whorl of two to eight fusedsepals. In the male flower thereceptacle is often flat, while in the bisexual and female flowers it is tubular, there are four to eightstamens with freefilaments and bilocularanthers. Theovary is superior with onecarpel containing a single erectanatropousovule. Thestyle is long and bears a singlestigma. The fruit is anachene or adrupe a fruit-like structure enclosed by the thickened lower part of the persistentcalyx. It contains a single seed with little or noendosperm and a straightembryo with thick fleshycotyledons. A number ofspecies are grown as ornamentalshrubs, notablyElaeagnus angustifolia (oleaster),Elaeagnus pungens,Elaeagnus umbellata andElaeagnus macrophylla, which are mainly grown asdeciduous or evergreen shrubs for their attractive foliage andHippophae rhamnoides (sea buckthorn) is grown for its bright orangeberries inautumn andwinter. The fruits of a number of species are edible, for example, those ofShepherdia argentea (Silver Buffalo Berry). Its fruits are used asjelly and are also eaten dried with sugar in various parts of theUnited States andCanada. The berries ofShepherdia canadensis (Russet Buffalo Berry) when dried or smoked are used as food byInuit,Yupik andAleut peoples. The berries ofHippophae rhamnoides are made into asauce inFrance and intojelly elsewhere. Thewood of this species isfine-grained and is used forwoodturning. The fruit of theJapanese shrubElaeagnus multiflora (Cherry Elaeagnus) are used inpreserves and are used inalcoholic beverage.[4]
Modernmolecular phylogenetics suggest the following relationships:[5]
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Fossil pollen ofElaeagnacites is described from the lateCretaceous (Santonian) ofChina andpollen similar to that of Elaeagnaceae is widespread in thePaleocene.[6] There are pollen evidence ofElaeagnus from the upperEoceneFlorissant Formation,Colorado, McGinitie's Wardell Ranch Flora locality in Colorado of middle to late middle Eocene and similar samples from the Washakie Basin Laney Shale Member of early Eocene.[7] A fossil †Elaeagnus orchidioides flower is recorded from the latePliocene ofWillershausen (Kalefeld),Hesse,Germany. There are two fossil wood records with extensive documentation of anatomical features: †Elaeagnus semiannulipora from the earlyMiocene ofYamagata,Japan, and †EIeagnaceoxylon shepherdioides, considered similar toShepherdia, from thePlioceneBeaufort Formation, northwesternBanks Island,Canada. Four fossil leaves have been described with diagnostic features ofElaeagnus from the lateMiocene of easternTibet, modern altitude of 3910 m The silverberry genusElaeagnus (Elaeagnaceae) reaches its greatest diversity (54 species) andendemism (36 species) in this area. The diversification ofElaeagnus in theQinghai-Tibet Plateau and adjacent areas might have been driven by continuous uplift at least since the lateMiocene, causing formation of complex topography and climate with high rainfall seasonality.[8]
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