biology

Saint Helena olive

Saint Helena olive is a biology topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Saint Helena olive rather than just read about it. In short: The Saint Helena olive (Nesiota elliptica) is an extinct species of flowering plant. It is the only member of the genus Nesiota.

Key takeaways

Saint Helena olive belongs to biology; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Saint Helena olive to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Saint Helena olive from memory before moving on to harder problems.

Reference excerpt

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.

Description The Saint Helena olive was native to the cloud forest found in the upland areas of the island above 750 metres (2,460 ft), with many historical records around Diana's Peak (the highest point on the island). 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.

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. A sample of DNA from the Saint Helena Olive is stored at Kew Gardens DNA bank. 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.

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.

Relationships of Phyliceae, after

Illustrations

Worked examples

Example 1 — a first encounter with Saint Helena olive

Start with the simplest possible case. Write down what Saint Helena olive claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In biology, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Saint Helena olive before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Saint Helena olive ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Saint Helena olive

In research: Saint Helena olive appears in biology research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Saint Helena olive in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Saint Helena olive is common in secondary-school and first-year university syllabi. It links to neighbouring topics Endemic flora of Saint Helena, Extinct flora of Africa, IUCN Red List extinct species, so understanding it makes those chapters shorter.
In everyday life: Look for Saint Helena olive outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Saint Helena olive in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Saint Helena olive means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Saint Helena olive out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Saint Helena olive in simple terms?

The Saint Helena olive (Nesiota elliptica) is an extinct species of flowering plant. It is the only member of the genus Nesiota.

Why does Saint Helena olive matter?

Because it connects several biology ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Saint Helena olive?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Saint Helena olive.