Elaeagnus

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Elaeagnus
Elaeagnus commutata USDA.jpg
Elaeagnus commutata
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Rosids
Order: Rosales
Family: Elaeagnaceae
Genus: Elaeagnus
L.
Species

See text

Elaeagnus distribution.svg

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

Habitat[edit]

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[edit]

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).

Cultivation[edit]

Elaeagnus species are widely cultivated for their showy, often variegated, foliage, and numerous cultivars and hybrids have been developed.[4]

E. angustifolia cultivated as bonsai

Notable species and hybrids in cultivation include:-

The cultivar 'Gilt Edge'[5] has gained the Royal Horticultural Society's Award of Garden Merit.

Other uses[edit]

E. umbellata is reputed to have a high amount of the carotenoid antioxidant, lycopene[6] and has been shown to display antioxidant properties effective against cancer mechanisms in vitro.[7] E. multiflora is among the nutraceutical plants that Chinese use both for food and medicine.[citation needed] Both of these species have small but abundant tasty berries.

Berries from a large-fruited cultivar

Ecology[edit]

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[edit]

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[edit]

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

Standard for Human Consumption[edit]

Notes[edit]

  1. ^ Sunset Western Garden Book. 1995. pp. 606–7. ISBN 978-0-376-03850-0. 
  2. ^ http://www.bonap.org/BONAPmaps2010/Elaeagnus.html
  3. ^ a b "Florida Exotic Pest Plant Council Invasive Plant Lists". Florida Exotic Pest Plant Council. Retrieved 6 February 2012. 
  4. ^ RHS A-Z encyclopedia of garden plants. United Kingdom: Dorling Kindersley. 2008. p. 1136. ISBN 1405332964. 
  5. ^ "Eleagnus × ebbengei 'Gilt Edge'". Royal Horticultural Society. Retrieved 25 July 2013. 
  6. ^ Fordham, Ingrid M.; Clevidence, Beverly A; Wiley, Eugene R.; Zimmerman, Richard H. (2001). "Fruit of autumn olive : A rich source of lycopene". HortScience 36 (6): 1136–7. ISSN 0018-5345. 
  7. ^ Wang, Shiow; Bowman, Linda; Ding, Min (2007). "Variations in Free Radical Scavenging Capacity and Antiproliferative Activity Among Different Genotypes of Autumn Olive (Elaeagnus umbellata)". Planta Medica 73 (5): 468–77. doi:10.1055/s-2007-967175. PMID 17566149. 
  8. ^ https://www.esma.ae/e-store/Default/StdDetails.aspx?std=3863

External links[edit]