Elaeagnus

Elaeagnus
American silverberry (Elaeagnus commutata)
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Rosales
Family:	Elaeagnaceae
Genus:	Elaeagnus L.
Species
See text

Elaeagnus /ˌɛliːˈæɡnəs/,^[1] silverberry or oleaster, is a genus of about 50–70 species of flowering plants in the family Elaeagnaceae.

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.^[2][3]

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).

Elaeagnus umbellata contains the carotenoid, lycopene.^[4]

Cultivation

Elaeagnus species are widely cultivated for their showy, often variegated, foliage, and numerous cultivars and hybrids have been developed.^[5]

E. angustifolia cultivated as bonsai

Notable species and hybrids in cultivation include:-

• Elaeagnus angustifolia
• Elaeagnus commutata
• Elaeagnus × ebbingei
• Elaeagnus macrophylla
• Elaeagnus multiflora
• Elaeagnus pungens
• Elaeagnus × reflexa
• Elaeagnus umbellata

The cultivar 'Gilt Edge'^[6] has gained the Royal Horticultural Society's Award of Garden Merit.

Berries from a large-fruited cultivar

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, and are therefore able to grow well in low-nitrogen soil. 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 exotic invasive species by the Florida Exotic Pest Plant Council.^[3]
• Because they increase fixed nitrogen levels in the soil, they can alter habitats by enabling species which require more fixed nitrogen to be more competitive, replacing other species which are themselves tolerant of soils with low levels of fixed nitrogen.
• The extra availability of fixed nitrogen in the plant makes its leaves more nutritious.

Selected species

Hybrids

• Elaeagnus × ebbingei (E. macrophylla × E. pungens)
• Elaeagnus × pyramidalis (E. commutata × E. multiflora)
• Elaeagnus × reflexa (E. pungens × E. glabra)

Standard for Human Consumption

• ISO 23394 has been promulgated to cover dried E. angustifolia for human consumption.^[7]

References

External links

Wikimedia Commons has media related to Elaeagnus.

Wikispecies has information related to: Elaeagnus

• eFloras Chinese Plant list: Elaeagnus
• Elaeagnus veteris-castelli holotype, sheet from Louis-Marie Herbarium (Laval University).
• 'Florida Exotic Pest Plant Council Invasive Plant Lists'