Saint Helena Olive - Nesiota elliptica

Photo: Saint Helena Olive by Rebecca Cairns-Wicks. The copyrighted photograph presented here may be freely used for any non-commercial purpose, but please credit the respective photographer. For commercial use, please contact the photographer directly. Please visit the 2003 IUCN Red List of Threatened Species - Photo Gallery for more information.

The St. Helena Olive was a small and spreading tree up to 4 (perhaps as high as 7) m tall. It had numerous branches with a dark brown to black bark. The oblong shaped and dark green leaves had curved tips, and its pale underside had flat-laying hairs. The branched inflorescence (flower stalk) of this species did not rise above the leaves. The fruits were 1-2 cm long hard and woody capsules, revealing the triangular shiny black seeds inside when split after reaching maturity. (Cronk 2000; Baillie and Stuart 2004; ARKive 2006)

The flowering time of this species was reported to be June to October. It is thought that Loveridgeana beattiei, an endemic fly, pollinates the St. Helena Olive. The tree is 99% self-incompatible, and so could not set seed with itself or closely related individuals. Its fruits took a year to mature (Cronk 2000). Seedlings have proven extremely difficult to cultivate (Jackson 1991). (Cairns-Wicks 2004; ARKive 2006)

The St. Helena Olive was endemic to the island of Saint Helena (British overseas territory of Saint Helena, Ascension and Tristan da Cunha) in the southern Atlantic Ocean, where it was known from localised subpopulation on the highest parts of the eastern central ridge (Cronk 2000). The last living specimens were found on Diana's Peak. (Cairns-Wicks 2004)

Image: The location of the island of Saint Helena, part of the British overseas territory of 'Saint Helena, Ascension and Tristan da Cunha' in the southern Atlantic Ocean (black dot in a red circle). This map is created by Peter Maas for The Sixth Extinction website. This image has been licensed under the Creative Commons Attribution Non-commercial No Derivatives 3.0 licence.

The St. Helena Olive became very rare in the 19th century, probably as a consequence of habitat loss, and by 1875 only 12 to 15 trees were recorded as growing on the northern side of Diana’s Peak. After a while this tree was thought to have become extinct, until a single tree was discovered on a precipitous cliff near Diana's Peak in August 1977. This single tree was found to suffer from numerous systemic fungal infections, which may have been exacerbated by damage sustained during attempts to conserve it. The last wild St. Helena Olive died on 11 October 1994, but the species continued to survive in cultivation. 

It proved extremely hard to root cuttings, and the species very rarely set good seeds, as it was 99% self-incompatible. A single successful cutting was grown from the last wild tree that died in 1994. This cutting to a 2 metre tall tree by the Endemic Plant Propagation Unit at Scotland, now known as the Environmental Conservation Section, St Helena, but was sadly lost in 1997. From this tree two raised seedlings were planted out in the Conservation Officer's garden at Pounceys. A third seedling was planted out near the main plant at Scotland, but did not survive. From the cutting at Scotland a fourth seedling was raised and planted beside the third seedling on the Peaks. The health of the smaller olive at Pounceys and the two on the Peaks declined and they were all dead by 1999. (ARKive 2006)

The last surviving seedling (see photo above) showed signs of ill health due to fungal infections and in 2003 deteriorated extremely quickly following a dry winter. In December 2003, despite extensive efforts to rejuvenate the species, the St. Helena olive was declared Extinct, as no other live material (plants, seeds or tissues) remains in local or international collections. (Baillie and Stuart 2004)

The St. Helena Olive was threatened by felling for timber and to make way for plantations, and the grazing of introduced goats. The self-incompatibility mechanism (99% self-incompatible) of this species made successful propagation difficult. Pests and systematic fungal infections affected the the survival as well. (Cairns-Wicks 2004; ARKive 2006)

Attempt to produce offspring has been attempted and several seedlings were raised and planted, but none survived (ARKive 2006). A Draft Recovery Action Plan has been made as well. (Cairns-Wicks 2004; ARKive 2006)

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The St. Helena Olive was the only representative of its genus. With the extinction of this species the whole genus became extinct. Although called the St. Helena olive it is unrelated to the true olive (Olea europaea). The closest living relatives are the other species in the family Rhamnaceae.

IUCN Red List of Threatened Species: Nesiota elliptica

St Helena olive - Nesiota elliptica - ARKive

ARKive. 2006. St Helena olive - Nesiota elliptica: More Information. Downloaded on 24 December 2006 from http://www.arkive.org/species/GES/plants_and_algae/Nesiota_elliptica/more_info.html.

Baillie, J.E.M., Hilton-Taylor, C. and Stuart, S.N. (Editors) 2004. 2004 IUCN Red List of Threatened Species. A Global Species Assessment. IUCN, Gland, Switzerland and Cambridge, UK. xxiv + 191 pp. 

Cairns-Wicks, R. 2004. Nesiota elliptica. In: IUCN 2006. 2006 IUCN Red List of Threatened Species. <www.iucnredlist.org>. Downloaded on 24 December 2006.

Cronk, Q.C.B. (2000) The Endemic Flora of St Helena. Anthony Nelson, Shropshire.

Jackson, A. (1991) Project Popeye – Saving the St Helena Olive. Preliminary report to the World Wide Fund for Nature (WWF Project No. 162/89). Wakehurst Place, RBG, Kew.