Elaeagnus Davidii

''Elaeagnus'' , silverberry or oleaster, is a genus of about 50–70 species of flowering plants in the family Elaeagnaceae.

Description

''Elaeagnus'' plants are deciduous or evergreen shrubs or small trees. The alternate leaves and the shoots are usually covered with tiny silvery to brownish scales, giving the plants a whitish to grey-brown colour from a distance. The flowers are small, with a four-lobed calyx and no petals; they are often fragrant. The fruit is a fleshy drupe containing a single seed; it is edible in many species. Several species are cultivated for their fruit, including ''E. angustifolia'', ''E. umbellata'', and ''E. multiflora'' (gumi). ''E. umbellata'' contains the carotenoid lycopene.

Taxonomy

The genus ''Elaeagnus'' was erected in 1754 by Carl Linnaeus, who attributed the name to Joseph Pitton de Tournefort. There is agreement that the name is based on Theophrastus's use of the Ancient Greek (, latinized to ) as the name of a shrub. The first part of the name, ''elae-'', is from , 'olive'. Sources differ on the origin of the second part: it may be from , '' Vitex agnus-castus'', the chaste tree, or from the Greek name for a kind of willow. In either case, the second part is derived from (), meaning 'pure', 'chaste'.

Species

''Elaeagnus'' comprises the following species:

* '' Elaeagnus angustata'' (Rehder) C.Y.Chang (China)
* '' Elaeagnus angustifolia'' L. – oleaster, Russian silverberry, or Russian olive (western Asia)
* '' Elaeagnus annamensis'' S.Moore
* '' Elaeagnus argyi'' H.Lév. (China)
* ''Elaeagnus bambusetorum'' Hand.-Mazz. (China)
* ''Elaeagnus bockii'' Diels (China)
* '' Elaeagnus bonii'' Lecomte
* '' Elaeagnus calcarea'' Z.R.Xu
* '' Elaeagnus caudata'' Schltdl. ex Momiy.
* '' Elaeagnus cinnamomifolia'' W.K.Hu & H.F.Chow (China)
* ''Elaeagnus commutata'' Bernh. ex Rydb. – American silverberry or wolf-willow (North America)
* '' Elaeagnus conferta'' Roxb. (southern Asia)
* '' Elaeagnus courtoisii'' Belval (China)
* '' Elaeagnus davidii'' Franch. (China)
* '' Elaeagnus delavayi'' Lecomte (China)
* '' Elaeagnus difficilis'' Servett. (China)
* '' Elaeagnus epitricha'' Momiy. ex H.Ohba
* '' Elaeagnus fasciculata'' Griff.
* '' Elaeagnus formosana'' Nakai ( Taiwan)
* '' Elaeagnus formosensis'' Hatus.
* ''Elaeagnus geniculata'' D.Fang
* '' Elaeagnus glabra'' Thunb. (eastern Asia)
* '' Elaeagnus gonyanthes'' Benth. (China)
* '' Elaeagnus griffithii'' Servett. (China)
* '' Elaeagnus grijsii'' Hance (China)
* '' Elaeagnus guizhouensis'' C.Y.Chang (China)
* '' Elaeagnus henryi'' Warb. ex Diels (China)
* '' Elaeagnus heterophylla'' D.Fang & D.R.Liang
* '' Elaeagnus hunanensis'' C.J.Qi & Q.Z.Lin
* '' Elaeagnus indica'' Servett.
* '' Elaeagnus infundibularis'' Momiy.
* '' Elaeagnus jiangxiensis'' C.Y.Chang (China)
* '' Elaeagnus jingdonensis'' C.Y.Chang (China)
* '' Elaeagnus kanaii'' Momiy. (China)
* '' Elaeagnus lanceolata'' Warb. (China)
* '' Elaeagnus lanpingensis'' C.Y.Chang (China)
* '' Elaeagnus laosensis'' Lecomte
* ''Elaeagnus latifolia'' L. (southern Asia)
* '' Elaeagnus lipoensis'' Z.R.Xu
* '' Elaeagnus liuzhouensis'' C.Y.Chang (China)
* '' Elaeagnus longiloba'' C.Y.Chang (China)
* '' Elaeagnus loureiroi'' Champ. (southern China)
* '' Elaeagnus luoxiangensis'' C.Y.Chang (China)
* '' Elaeagnus luxiensis'' C.Y.Chang (China)
* '' Elaeagnus macrantha'' Rehder (China)
* ''Elaeagnus macrophylla'' Thunb. (eastern Asia)
* '' Elaeagnus magna'' (Servett.) Rehder (China)
* '' Elaeagnus matsunoana'' Makino
* '' Elaeagnus maximowiczii'' Servett.
* '' Elaeagnus micrantha'' C.Y.Chang (China)
* '' Elaeagnus mollis'' Diels (China)
* '' Elaeagnus montana'' Makino
* '' Elaeagnus morrisonensis'' Hayata ( Taiwan)
* ''Elaeagnus multiflora'' Thunb. – cherry silverberry or gumi (eastern Asia)
* '' Elaeagnus murakamiana'' Makino
* '' Elaeagnus nanchuanensis'' C.Y.Chang (China)
* '' Elaeagnus obovata'' H.L.Li (China)
* '' Elaeagnus obovatifolia'' D.Fang
* '' Elaeagnus obtusa'' C.Y.Chang (China)
* '' Elaeagnus oldhamii'' Maxim. (China)
* '' Elaeagnus ovata'' Servett. (China)
* '' Elaeagnus pallidiflora'' C.Y.Chang (China)
* '' Elaeagnus parvifolia'' Wall. ex Royle (central Asia)
* '' Elaeagnus pilostyla'' C.Y.Chang (China)
* '' Elaeagnus pingnanensis'' C.Y.Chang (China)
* ''Elaeagnus pungens'' Thunb. – silverthorn (Japan)
* '' Elaeagnus pyriformis'' Hook.f. (eastern Himalaya)
* '' Elaeagnus retrostyla'' C.Y.Chang (China)
* '' Elaeagnus rhamnoides'' (L.) A.Nelson
* '' Elaeagnus rivularis'' Merr.
* '' Elaeagnus rotundata'' Nakai
* '' Elaeagnus sarmentosa'' Rehder (China)
* '' Elaeagnus schlechtendalii'' Servett. (China)
* '' Elaeagnus songarica'' Schltr.
* '' Elaeagnus s-stylata'' Z.R.Xu
* '' Elaeagnus stellipila'' Rehder (China)
* '' Elaeagnus takeshitai'' Makino
* '' Elaeagnus taliensis'' C.Y.Chang (China)
* '' Elaeagnus tarokoensis'' S.Y.Lu & Yuen P.Yang
* '' Elaeagnus thunbergii'' Servett. (China)
* '' Elaeagnus tonkinensis'' Servett. (southeastern Asia)
* '' Elaeagnus tricholepis'' Momiy.
* '' Elaeagnus triflora'' Roxb. (southeastern Asia, northeast Australia)
* '' Elaeagnus tubiflora'' C.Y.Chang (China)
* '' Elaeagnus tutcheri'' Dunn (southern China)
* '' Elaeagnus umbellata'' Thunb. – Japanese silverberry or autumn olive (eastern Asia)
* '' Elaeagnus viridis'' Servett. (China)
* '' Elaeagnus wenshanensis'' C.Y.Chang (China)
* '' Elaeagnus wilsonii'' H.L.Li (China)
* '' Elaeagnus wushanensis'' C.Y.Chang (China)
* '' Elaeagnus xichouensis'' C.Y.Chang (China)
* '' Elaeagnus xingwenensis'' C.Y.Chang
* '' Elaeagnus xizangensis'' C.Y.Chang (China)
* '' Elaeagnus yoshinoi'' Makino
* '' Elaeagnus yunnanensis'' Servett.

Species names with uncertain taxonomic status

The status of the following species is unresolved:

* ''Elaeagnus arakiana'' Koidz.
* ''Elaeagnus asakawana'' Sa.Kurata
* ''Elaeagnus attenuata'' Nakai
* ''Elaeagnus crocea'' Nakai
* ''Elaeagnus cyanea'' Aiton ex Steud.
* ''Elaeagnus emarginata'' Colla
* ''Elaeagnus fasciculata'' (Wall. ex Steud.) A.Nelson
* ''Elaeagnus fragrans'' Nakai
* ''Elaeagnus fruticosa'' (Lour.) A.Chev.
* ''Elaeagnus fusca'' Pépin ex Lem.
* ''Elaeagnus higoensis'' Nakai
* ''Elaeagnus kiusiana'' Nakai
* ''Elaeagnus laetevirens'' Lindb.
* ''Elaeagnus latifolia'' Lour.
* ''Elaeagnus mayeharai'' Nakai
* ''Elaeagnus nagasakiana'' Nakai
* ''Elaeagnus numajiriana'' Makino
* ''Elaeagnus oleaster'' L.
* ''Elaeagnus pauciflora'' C.Y. Chang (China)
* ''Elaeagnus philippinensis'' Perrott. – lingaro berry (Philippines)
* ''Elaeagnus'' × ''pyramidalis'' Browicz & Bugala (''E. commutata'' × ''E. multiflora'')
* ''Elaeagnus oxycarpa'' Schltdl. (China)
* ''Elaeagnus rotundifolia'' (Parry) A.Nelson
* ''Elaeagnus sativa'' Dippel
* ''Elaeagnus undulata'' auct.
* ''Elaeagnus utilis'' A.Nelson
* ''Elaeagnus veteris-castelli'' Lepage
* ''Elaeagnus yakusimensis'' Masam.

Hybrids

The following hybrids have been described:
* ''Elaeagnus'' × ''maritima'' Koidz.
* ''Elaeagnus'' × ''reflexa'' E.Morren & Decne. (''E. pungens'' × ''E. glabra'')
* ''Elaeagnus'' × ''submacrophylla'' Servett. (''E. macrophylla'' × ''E. pungens'')

Habitat

The vast majority of the species are native to temperate and subtropical regions of Asia. ''Elaeagnus triflora'' extends from Asia south into northeastern Australia, while ''E. commutata'' is native to North America, and ''Elaeagnus philippinensis'' is native to the Philippines. One of the Asian species, ''E. angustifolia,'' may also be native in southeasternmost Europe, though it may instead be an early human introduction there. Also, several Asiatic species of ''Elaeagnus'' have become established as introduced species in North America, with some of these species being considered invasive, or even designated as noxious, in portions of the United States.

Ecology

''Elaeagnus'' species are used as food plants by the larvae of some Lepidoptera species including '' Coleophora elaeagnisella'' and the Gothic moths. The thorny shrubs can also provide good nesting sites for birds.

Nitrogen fixation

Many ''Elaeagnus'' species harbor nitrogen-fixing organisms in their roots, so are able to grow well in low-nitrogen soils. This ability results in multiple ecological consequences where these ''Elaeagnus'' species are present. They can become invasive in many locations where they are established as exotic species. Two species ('' E. pungens'' and '' E. umbellata'') are currently rated as category II noxious, invasive species in many world regions and by the Florida Exotic Pest Plant Council.

Cultivation

''Elaeagnus'' species are widely cultivated for their showy, often variegated, foliage, and numerous cultivars and hybrids have been developed.

The fruit is acid and somewhat astringent. It makes good tarts.

Notable species and hybrids in cultivation include:-
*'' Elaeagnus angustifolia''
*''Elaeagnus commutata''
*''Elaeagnus macrophylla''
*''Elaeagnus multiflora''
*''Elaeagnus pungens''
*''Elaeagnus'' × ''reflexa''
* ''Elaeagnus'' × ''submacrophylla'' (syn. ''E.'' × ''ebbingei'')
*'' Elaeagnus umbellata''

The hybrid ''Elaeagnus'' × ''submacrophylla'' and the cultivar 'Gilt Edge' have gained the Royal Horticultural Society's Award of Garden Merit.

References

External links

''eFloras'' Chinese Plant list: ''Elaeagnus''

{{Taxonbar, from=Q161042

Rosales genera