Saint Helena olive

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Saint Helena olive
Nesiota elliptica.jpg
Status iucn3.1 EX.svg
Extinct  (2003)  (IUCN 3.1) [1]
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Rosales
Family: Rhamnaceae
Tribe: Phyliceae
Genus:† Nesiota
Hook.f.
Species:
†N. elliptica
Binomial name
†Nesiota elliptica

The Saint Helena olive (Nesiota elliptica) is an extinct species of flowering plant. It is the only member of the genus Nesiota. It was endemic to the island of Saint Helena in the South Atlantic Ocean. Despite its name, it is unrelated to the true olive ( Olea europaea ), but is instead a member of the family Rhamnaceae, the family which contains buckthorns and jujube. The last remaining tree in the wild died in 1994, and the last remaining individual in cultivation died in December 2003, despite conservation efforts. It is thus a prime example of recent plant extinction. The Saint Helena olive belongs to the tribe Phyliceae, which are mostly endemic to Southern Africa.

Contents

Description

The Saint Helena Olive was native to the cloud forest found in the upland areas of the island above 750 metres, with many historical records around Diana's Peak (the highest point on the island). [2] It grew as a small, low growing spreading tree with prolific branching. The bark was dark brown to black. The leaves were oblong in shape and dark green, with downward curving tips. The undersides of the leaves were pale with hairs that lay flat along the leaf. During the flowering season, which is presumed to have run from June to October, the tree bore tightly packed pink flowers on branched inflorescences. The flowers are presumed to have been pollinated by the local endemic hoverfly species Sphaerophoria beattiei. The fruit took a year to mature, and consisted of a hard woody capsule containing shiny triangular black seeds. [3]

Extinction

The Saint Helena olive was already rare by the 19th century due to deforestation and grazing by introduced goats, and was previously thought to be extinct until a single living specimen was discovered in 1977. It was highly self-incompatible, meaning that most seeds produced with itself or close relatives would fail, making it extremely difficult to grow seedlings, given that the population size for the plant had probably always been low. Despite immense effort, only a single cutting of the plant was able to be cultivated, with a handful of seedlings grown from it. The original wild plant died in 1994, making the species extinct in the wild. The final known specimen in cultivation, a seedling of the cutting, which had been the only surviving plant since 1999, died in 2003 from fungus and termite infestation, making the species totally extinct. [3] A sample of DNA from the Saint Helena Olive is stored at Kew Gardens DNA bank. [4] The Saint Helena Olive is one of a number of plant species to have gone extinct on Saint Helena since the arrival of the Portuguese in 1502, including Trochetiopsis melanoxylon, Acalypha rubrinervis, Wahlenbergia roxburghii, and Heliotropium pannifolium, with Lachanodes arborea and Trochetiopsis erythroxylon also extinct in the wild. [5]

Phylogenetics

The Saint Helena olive is part of the tribe Phyliceae within Rhamnaceae. The Phyliceae are mostly endemic to Southern Africa, particularly the Fynbos region of South Africa. [6]

Relationships of Phyliceae, after [6]

Phyliceae

Noltea

Phylica

Trichocephalus

†Nesiota

See also

Related Research Articles

<span class="mw-page-title-main">Saint Helena scrub and woodlands</span>

The Saint Helena scrub and woodlands ecoregion covers the volcanic island of Saint Helena in the South Atlantic Ocean. The island's remote location gave rise to many endemic species. First discovered and settled in the 1500s, the island has been degraded by human activities. Most of its native habitat has been destroyed, and many of its unique plants and animals are extinct or endangered.

Lachanodes arborea, the she cabbage tree, is a small tree in the family Asteraceae. It is an endangered endemic of the island of Saint Helena in the South Atlantic Ocean. It is now extinct in the wild.

<i>Melanodendron</i> Genus of trees

Melanodendron is a genus of trees in the family Asteraceae, with only one species, Melanodendron integrifolium, native to the island of Saint Helena. It is related to the Saint Helenan gumwoods and is the most common of the remaining cabbage tree species of Saint Helena, although it is considered endangered due to the restricted population size.

<i>Acalypha rubrinervis</i> Extinct species of flowering plant

Acalypha rubrinervis is an extinct plant in the spurge family (Euphorbiaceae), from the island of Saint Helena in the South Atlantic Ocean. It was called string tree on account of the thin pendulous inflorescences which resembled red strings. Disturbance following human settlement on the island destroyed its habitat and it was last seen in the 19th century. It is thus one of a number of island plants to have been driven to extinction by human activity.

<i>Pladaroxylon</i>

Pladaroxylon is a genus of trees in the tribe Senecioneae within the family Asteraceae.

<span class="mw-page-title-main">Flora of Saint Helena</span>

The flora of Saint Helena, an isolated island in the South Atlantic Ocean, is exceptional in its high level of endemism and the severe threats facing the survival of the flora. In phytogeography, it is in the phytochorion St. Helena and Ascension Region of the African Subkingdom, in the Paleotropical Kingdom.

<i>Trochetiopsis erythroxylon</i> Species of flowering plant

Trochetiopsis erythroxylon, the Saint Helena redwood, is a species of plant, now extinct in the wild. It was formerly abundant enough in the upland parts of the island of Saint Helena for early settlers in the 17th century to use the timber to make their homes. It became extinct in the 1950's due to deforestation as its habitat was cleared to make way for pasture, timber and fuel.

<i>Trochetiopsis ebenus</i> Species of flowering plant

Trochetiopsis ebenus, the dwarf ebony or Saint Helena ebony, is a species of flowering plant that is endemic to the island of Saint Helena in the southern Atlantic Ocean. It is not related to the ebony of commerce, but is instead a member of the mallow family, Malvaceae. Saint Helena ebony is now critically endangered in the wild, being reduced to two wild individuals on a cliff, but old roots are sometimes found washed out of eroding slopes. These are collected on the island a used for inlay work, an important craft on Saint Helena. A related species, Trochetiopsis melanoxylon is now completely extinct.

<i>Trochetiopsis</i> Genus of flowering plants

The flowering plant genus Trochetiopsis consists of two extant and one extinct species endemic to the island of Saint Helena. They were formerly placed in the family Sterculiaceae, but this is included in the expanded Malvaceae in the APG and most subsequent systematics.

<i>Commidendrum robustum</i> Species of flowering plant

Commidendrum robustum, the Saint Helena gumwood, is a species of tree endemic to Saint Helena, Ascension and Tristan da Cunha. Though it is now comparatively rare, it was once one of the most abundant trees of mid-elevations of the island of Saint Helena in the South Atlantic Ocean. A small tree to 7–8 m, it was cut extensively for fuel in the early years of settlement of the island by the English East India Company. It has given its name to certain placenames on the island such as "Gumwoods". It is one of several species in the endemic genus Commidendrum.

<i>Lobelia scaevolifolia</i> Genus of flowering plants

Lobelia scaevolifolia is a species of the plant family Campanulaceae. It is endemic to the island of Saint Helena in the South Atlantic Ocean. It was at one time placed as the only species, Trimeris scaevolifolia, in the genus Trimeris. Its common name is St. Helena lobelia.

<i>Mellissia</i> Genus of flowering plants

Mellissia was formerly a monotypic genus in the family Solanaceae with the single species, Mellissia begoniifolia, endemic to the island of Saint Helena. It was named by Joseph Dalton Hooker in honour of John Charles Melliss, a 19th-century engineer and amateur naturalist who worked on Saint Helena. The plant is now known correctly as Withania begoniifolia (Roxb.) Hunz. & Barboza, the genus Mellissia having been subsumed in the genus Withania.

<i>Petrobium</i> Genus of flowering plants

Petrobium is a genus in the family Asteraceae.

<i>Commidendrum rugosum</i> Species of flowering plant

Commidendrum rugosum, known as scrubwood, is a species of flowering plant in the family Asteraceae.

Sium burchellii, known commonly as dwarf jellico, is a species of flowering plant in the family Apiaceae. It is endemic to Saint Helena. It grows on steep island cliffs. It is threatened by the fragmentation of its small populations, introduced species of plants, landslides, and possibly hybridization with Sium bracteatum.

<i>Frankenia portulacifolia</i> Species of flowering plant

Frankenia portulacifolia, also called Saint Helena tea or tea plant, is a species of salt-tolerant plant in the Frankeniaceae family. It is endemic to the islands of Saint Helena, Ascension and Tristan da Cunha. Its natural habitats are inhospitable, dry and rocky areas and rocky shores, often on weathered volcanic ash. As its total population has been estimated at only around 3,500 individuals, it is currently classified as Critically Endangered by the IUCN.

<i>Phylica polifolia</i> Species of flowering plant

Phylica polifolia, also called rosemary or Saint Helena rosemary, is a species of plant in the family Rhamnaceae. It is endemic to Saint Helena. Its natural habitats are rocky areas and rocky shores.

<i>Wahlenbergia angustifolia</i> Species of flowering plant

Wahlenbergia angustifolia, also called small bellflower, is a species of plant in the family Campanulaceae. It is endemic to Saint Helena. Its natural habitat is rocky areas. It is endangered because of habitat loss.

Eragrostis episcopulus, the cliff hair grass, is a species of grass endemic to St. Helena. The species is classified as Critically Endangered because of its extremely restricted range and population fragmentation.

References

  1. ↑ Lambdon, P.W.; Ellick, S. (2016). "Nesiota elliptica". IUCN Red List of Threatened Species . 2016: e.T37598A67372241. doi: 10.2305/IUCN.UK.2016-1.RLTS.T37598A67372241.en . Retrieved 19 November 2021.
  2. ↑ Lambdon, P.W. & Ellick, S. 2016. Nesiota elliptica . The IUCN Red List of Threatened Species 2016: e.T37598A67372241. Accessed on 18 October 2022.
  3. 1 2 "St Helena olive videos, photos and facts - Nesiota elliptica | Arkive". 2019-01-31. Archived from the original on 2019-01-31. Retrieved 2021-12-09.
  4. ↑ "St Helena olive". Temperate House | Kew Gardens. Retrieved 2022-04-23.
  5. ↑ Lambdon, Phil; Cronk, Quentin (2020). "Extinction Dynamics Under Extreme Conservation Threat: The Flora of St Helena". Frontiers in Ecology and Evolution. 8: 41. doi: 10.3389/fevo.2020.00041 . ISSN   2296-701X.
  6. 1 2 van Santen, Marit; Linder, Hans Peter (January 2020). "The assembly of the Cape flora is consistent with an edaphic rather than climatic filter". Molecular Phylogenetics and Evolution. 142: 106645. doi:10.1016/j.ympev.2019.106645. PMID   31610230. S2CID   204704517.
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