Olea europaea L.

First published in Sp. Pl.: 8 (1753)
This species is accepted
The native range of this species is Africa, Medit. to S. Central China. It is a shrub or tree and grows primarily in the subtropical biome. It is used to treat unspecified medicinal disorders, has environmental uses and social uses, as animal food and a medicine and for fuel and food.

Descriptions

The Useful Plants of Boyacá project

Distribution
Cultivated in Colombia.
Conservation
Least concern.
Ecology
Alt. 1990 - 2620 m.
Morphology General Habit
Shrub or tree.
[UPB]

Bernal, R., Gradstein, S.R. & Celis, M. (eds.). 2015. Catálogo de plantas y líquenes de Colombia. Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá. http://catalogoplantasdecolombia.unal.edu.co

Distribution
Cultivada en Colombia; Alt. 1990 - 2620 m.; Andes.
Morphology General Habit
Arbusto, arbolito, árbol
[CPLC]

Kew Species Profiles

General Description
Kew's Herbarium contains a wreath of folded olive leaves which was found in the sarcophagus of King Tutankhamun and is over 3,300 years old.

Olive trees (Olea europaea) have long represented wealth, abundance, power and peace. The olive has been a symbol of the Mediterranean since time immemorial and has a reputation for long life, nourishment and its ability to thrive in tough conditions.

Its primary product, olive oil, is revered throughout the world for its distinctive flavour. Homer called it 'liquid gold'. In ancient Greece athletes rubbed olive oil over their bodies and victorious competitors received no trophies or medals - instead the symbol of supreme honour was the olive wreath placed on their heads.

There are claims of 1,600 year-old trees still producing fruit.

Species Profile
Geography and distribution

This species is widely distributed across the Mediterranean region, Africa and Asia. 

Description

Overview:  Olea europaea  is an evergreen shrub or tree, which grows up to 15 m tall. It is slow to mature but can live for hundreds of years.

Leaves:  The leaves are borne in opposite pairs. The leaves are evergreen, 3 to 9 cm long, elliptic, and silvery in appearance.

Flowers:  The flowers are borne in axillary clusters, with a four-lobed calyx, and a four-lobed corolla. The two stamens (male parts) project beyond the mouth of the flower.

Fruits:  The fruit has a hard endocarp (the olive stone), which is surrounded by a fleshy, edible mesocarp.

Subspecies

Six genetically distinct subspecies are currently recognised.

Subspecies  europaea  is distributed around the Mediterranean as both the cultivated olive (var.  europaea ) and its feral relative (var. sylvestris ).Subspecies  cerasiformis  is restricted to the island of Madeira.Subspecies  guanchicaoccurs only on the Canary Islands.Subspecies  maroccana  is to be found as a small population at the southern end of the High Atlas Mountains of Morocco.The isolated Saharan massifs of the Hoggar, Air and Jebel Marra also have a distinct subspecies,  laperrinei .The remaining subspecies,  cuspidata , occurs widely through eastern and southern Africa, Arabia, and across Asia as far as southern China.

There are over 1,000 cultivars of olive, which have much larger, fleshier fruits (drupes) than their wild ancestor, which grows throughout the Mediterranean.

Uses History

Grown in the Mediterranean for over 5,000 years, the olive has shaped the landscape and culture of the region: 90% of all olives are produced in the Mediterranean. It is the region's most versatile and valuable crop with the fruit, oil and leaves having been used for food, fuel, medicine and embalming. 

The birth of olive-farming is shrouded in the mists of time. Discoveries of olive stones at archaeological sites in Israel show at least 20,000 years of use and by 5,000 years ago olives had been taken into cultivation and spread throughout the Levant. Domestication may have taken place in the eastern Mediterranean region, or in the region of the Nile Delta where the climate of the time would have been more suitable for cultivation. Today, there are thought to be around 1,000 million olive trees in the world.

Harvesting

Olives are harvested in autumn. If they are to become table olives they are soaked in water for five days to extract the bitter phenolic compounds such as oleuropein. The fruit is then cured in brine for around four weeks. Green olives are unripe, whereas black olives are ripe and less bitter. Olives are eaten as snacks or appetisers with a variety of accompaniments, and are a key ingredient of Mediterranean cooking.

Olive oil

Olive oil is obtained from the fruit. Shortly after harvesting, the fruit is cleaned and processed into a paste from which the oil is extracted. Olive oil is classified according to the production method and the oleic acid content. Virgin or cold-pressed olive oil is obtained by pressing alone and contains up to 2% oleic acid. Refined olive oil is obtained with the use of heat or solvent extraction and requires further processing to yield edible oil (it contains up to 3.3% oleic acid). The leftover cake is used as a source of inedible industrial-grade oil (containing more than 3.3% oleic acid), and is also used in livestock feed and compost. 

Diet

Olive oil is used for food, cooking and for a multitude of therapeutic purposes. 

The safe dosage for adults is two tablespoons (28 g) of olive oil per day. Evidence suggests that people whose diets include olive oil have a reduced risk of developing breast and colorectal cancers. Likewise, a diet rich in olive oil (and low in saturated fats) is associated with reduced risk of cardiovascular disease, high cholesterol levels and high blood pressure.

The beneficial qualities of olive oil have been attributed to the fatty-acid composition and the presence of phenolic compounds, which seem to have antioxidant, vasodilating, antiplatelet and anti-inflammatory effects. Kew is investigating how the waste products of olive oil production could be used as sources of compounds for medicines to treat cardio-vascular disease.

Other uses

The fine texture and intricate grain of olive wood is sought after for turnery and furniture, although it is difficult to work with due to the density (it is very hard and heavy). Olive wood and olive stones are excellent for fuel.

Olive trees are planted for ornamental purposes, as firebreaks and to control soil erosion in Mediterranean climates.

Millennium Seed Bank: Seed Storage

Kew's Millennium Seed Bank Partnership aims to save plant life world wide, focusing on plants under threat and those of most use in the future. Seeds are dried, packaged and stored at a sub-zero temperature in our seed bank vault.

Number of seed collections stored in the Millennium Seed Bank:  11

Seed storage behaviour:  Published literature compiled in the Seed Information Database (SID) indicate that this species' seeds survive drying to low moisture content and cooling to sub-zero temperatures and are thus amenable to long-term storage in facilities such as the Millennium Seed Bank. However, survival in storage may be quite short, and more research is needed.

Germination testing:  Collections so far tested at the MSB have failed to pass germination tests. However, seeds remaining at the end of the tests are healthy, indicating dormancy rather than low viability, and work is continuing to establish appropriate dormancy-breaking treatments.

Composition values:  Oil content: 1 - 41.9 %

Cultivation

Young olive plants are grown from seed in the Arboretum Nursery. It has been noted that germination is spasmodic, taking from a few weeks to a few months. The compost used as a growing medium is an open, gritty, free-draining mix. 

The seedlings are pricked out into 'air pots'. Air pots prevent the plants from becoming pot-bound by encouraging the roots to grow outwards rather than spiralling. Planting out into the required position in the garden can be carried out straight from the air pot. The glasshouse zone in which the seedlings are grown is kept at a minimum temperature of 5˚C. Only natural light is provided. The young plants are well watered and not allowed to dry out.

Many of the trees growing in the Mediterranean Garden are over 100 years old, having survived transplantation whilst mature to provide instant impact. These trees were sourced from a nursery in northern Italy, which purchases them from land-owners when they need to remove or replace them, and hence ensures a longer life for these trees. 

This species at Kew

The oldest of Kew's herbarium specimens is a wreath of folded olive leaves, which was found in the sarcophagus of King Tutankhamun. This well-preserved olive wreath is over 3,300 years old. Details of specimens of Olea europaea , including images, are available online in the Herbarium Catalogue.

In the summer of 2006 several mature trees were planted in a newly-landscaped Mediterranean setting. These included specimens of cork oak ( Quercus suber ), stone pine ( Pinus pinea ) and an olive ( Olea europaea ).

Tony Hall, who manages this collection, notes that olives respond well to the sandy, free-draining soil at Kew. In the winter of 2008 they survived snow, frost and temperatures of -7˚C. So far, flowers and small fruits have been observed, but ripening of the fruits has yet to occur at Kew.

Distribution
Egypt, Greece, Italy, Spain, Tunisia, Turkey
Ecology
Seasonally dry Mediterranean habitats, or bushland vegetation in the tropics.
Conservation
Olea europaea has not yet been assessed for the IUCN Red List.
Hazards

None known.

[KSP]

Bernal, R., G. Galeano, A. Rodríguez, H. Sarmiento y M. Gutiérrez. 2017. Nombres Comunes de las Plantas de Colombia. http://www.biovirtual.unal.edu.co/nombrescomunes/

Vernacular
acebuche, aceituna, olivo, olivo europeo
[UNAL]

Distribution
Biogeografic region: Andean. Elevation range: 1990–2620 m a.s.l. Cultivated in Colombia. Colombian departments: Bogotá DC, Boyacá, Cundinamarca.
Habit
Shrub, Small tree, Tree.
Ecology
Habitat according IUCN Habitats Classification: forest and woodland, artificial - terrestrial.
Vernacular
Aceituno, Olivo
[UPFC]

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit
Evergreen shrub or tree, up to c. 20 m tall, with a hard wood; bark of trunk rough, dark brown
Morphology Stem
Young stems glabrous, ± 4-angular in cross-section
Morphology Leaves
Leaves leathery; petiole 1–13 mm long; blade lanceolate to elliptic, 2–9.5 x 0.4–2.5 cm, cuneate at the base, acute to obtuse and apiculate at the apex, glossy dark green on upper surface, densely covered with small circular scales on lower surface giving a silvery or golden appearance
Morphology Reproductive morphology Inflorescences
Inflorescences with many sweetly scented flowers
Morphology Reproductive morphology Flowers Calyx
Calyx cup-shaped, c. 0.75 mm long, with minute lobes
Morphology Reproductive morphology Flowers Corolla
Corolla c. 2.5 mm long, white; lobes elliptic-acute, much longer than the tube
Morphology Reproductive morphology Flowers Androecium Stamens Anthers
Anthers c. 1.5 mm long
Morphology Reproductive morphology Fruits
Drupe 5–60 x 4–20 mm, ellipsoid to subglobose.
[FSOM]

Uses

Use Gene Sources
Crop wild relatives which may possess beneficial traits of value in breeding programmes (State of the World's Plants 2016).
Use Medicines Unspecified Medicinal Disorders
Medicinal (Instituto Humboldt 2014).
[UPB]

Use
Edible fruits, edible oil, fuel, attractive wood, soil erosion control, ornamental.
[KSP]

Use Animal Food
Used as animal food.
Use Environmental
Environmental uses.
Use Fuel
Used for fuels.
Use Gene Sources
Used as gene sources.
Use Food
Used for food.
Use Materials
Used as material.
Use Medicines
Medical uses.
Use Social
Social uses.
[UPFC]

Common Names

English
Olive
Spanish
Olivo, aceituno.

Sources

  • Art and Illustrations in Digifolia

    • Digital Image © Board of Trustees, RBG Kew
  • Catálogo de Plantas y Líquenes de Colombia

    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Colombian resources for Plants made Accessible

    • ColPlantA 2021. Published on the Internet at http://colplanta.org
    • http://creativecommons.org/licenses/by/3.0/
  • Flora of Somalia

    • Flora of Somalia
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Herbarium Catalogue Specimens

    • Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by/3.0/
  • Kew Backbone Distributions

    • The International Plant Names Index and World Checklist of Vascular Plants 2023. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2022 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0
  • Kew Living Collection Database

    • Common Names from Royal Botanic Gardens, Kew Living Collection https://www.kew.org/
  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2023. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2022 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0
  • Kew Science Photographs

    • Copyright applied to individual images
  • Kew Species Profiles

    • Kew Species Profiles
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Universidad Nacional de Colombia

    • ColPlantA database
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Useful Plants and Fungi of Colombia

    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Useful Plants of Boyacá Project

    • ColPlantA database
    • http://creativecommons.org/licenses/by-nc-sa/3.0
    • http://creativecommons.org/licenses/by/3.0/