biology

Quassia

Quassia 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 Quassia rather than just read about it. In short: Quassia ( or ) is a plant genus in the family Simaroubaceae. Its size is disputed; some botanists treat it as consisting of only one species, Quassia amara from tropical South America, while others treat it in a wide circumscription as a pantropical genus containing up to 40 species of trees and shrubs.

Key takeaways

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

Reference excerpt

Quassia ( or ) is a plant genus in the family Simaroubaceae. Its size is disputed; some botanists treat it as consisting of only one species, Quassia amara from tropical South America, while others treat it in a wide circumscription as a pantropical genus containing up to 40 species of trees and shrubs.

Taxonomy The genus was first published in Carl Linnaeus's book Species Plantarum ed. 2. on page 553 in 1762. The genus was named after a former slave from Suriname, Graman Quassi in the eighteenth century. He discovered the medicinal properties of the bark of Quassia amara. In 1962, Dutch botanist Hans Peter Nooteboom (1934–2022) had taken a very broad view of the genus Quassia L. and included therein various genera including, Hannoa Planch., Odyendyea (Pierre) Engl., Pierreodendron Engl., Samadera Gaertn., Simaba Aubl. and Simarouba Aubl. . Then in 2007, DNA sequencing, and phylogenetic analyses was carried out on members of the Simaroubaceae family. It found that genus Samadera was a sister to Clade V and that genus Quassia was also a sister to Clade V but they had separate lineages. This suggested the splitting up of genera Quassia again, with all Nooteboom's synonyms listed above being resurrected as independent genera. This includes Samadera indica Gaertn. as the accepted name for Quassia indica. The ornamental Quassia amara L., which is occasionally planted in Singapore, remains in genus Quassia.

Distribution Members of the genus are found in the Tropics throughout the world. Countries and regions where species are native include: Andaman Islands, Angola, Bangladesh, Belize, Benin, Bismarck Archipelago, Borneo, northern and northeastern Brazil, Burkina, Cabinda, Cambodia, Cameroon, Central African Republic, Chad, Colombia, Comoros, Congo, Costa Rica, El Salvador, Equatorial Guinea, Gabon, Gambia, Ghana, Guatemala, Guinea, Guinea-Bissau, Gulf of Guinea Islands, Honduras, India, Ivory Coast, Kenya, Laos, Leeward Islands, Liberia, Madagascar, Malaya, Mali, Central, Southeast and Southwest Mexico, Myanmar, New Guinea, Nicaragua, Niger, Nigeria, Northern Territory, Panamá, Philippines, Queensland, Senegal, Sierra Leone, Solomon Islands, Sri Lanka, Sudan, Sulawesi, Sumatera, Tanzania, Togo, Trinidad-Tobago, Uganda, Venezuela, Vietnam, Windward Islands, Zambia, and Zaïre. The plant is naturalised in the following places: Cuba, Dominican Republic, Haiti, Jamaica, Jawa, and Puerto Rico.

Species The only accepted species of the genus, by Plants of the World Online as of November 2023 is: Quassia amara L. Although World Flora Online accepts 16 species;

There are also taxa that have not been assigned a formal status:

The genus has been verified by the United States Department of Agriculture and the Agricultural Research Service (Germplasm Resources Information Network) and they only list 6 species; Quassia amara, Quassia cedron (syn. Simaba cedron, Quassia excelsa (syn. Picrasma excelsa), Quassia indica (syn. Samadera indica Gaertn.), Quassia simarouba (syn. Simarouba amara Aubl.) and Quassia undulata.

Uses It is the source of the quassinoids such as quassin and neo-quassin. Simalikalactone D is a quassinoid that is extracted from Quassia africana for antiviral properties.

References

External links Media related to Quassia at Wikimedia Commons Data related to Quassia at Wikispecies

Illustrations

Worked examples

Example 1 — a first encounter with Quassia

Start with the simplest possible case. Write down what Quassia 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 Quassia 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 Quassia 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 Quassia

In research: Quassia 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 Quassia 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: Quassia is common in secondary-school and first-year university syllabi. It links to neighbouring topics Botanical taxa named by Carl Linnaeus, Plant toxin insecticides, Plants described in 1762, so understanding it makes those chapters shorter.
In everyday life: Look for Quassia 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 Quassia in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Quassia 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 Quassia out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Quassia in simple terms?

Why does Quassia 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 Quassia?

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 Quassia.