biology

Placospermum

Placospermum 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 Placospermum rather than just read about it. In short: Placospermum is a monotypic genus of large tree in the plant family Proteaceae. The single species; Placospermum coriaceum, commonly known as rose silky oak or plate-seeded oak is endemic to the wet tropical rainforests of northeastern Queensland, Australia.

Key takeaways

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

Reference excerpt

Placospermum is a monotypic genus of large tree in the plant family Proteaceae. The single species; Placospermum coriaceum, commonly known as rose silky oak or plate-seeded oak is endemic to the wet tropical rainforests of northeastern Queensland, Australia.

History The genus and species were first formally scientifically described in 1924 by Cyril T. White and William D. Francis. The precise relationships of the genus were unclear, though it was clear it was an early offshoot within the Proteaceae and retained primitive characteristics, until Lawrie Johnson and Barbara G. Briggs classified it in the subfamily Persoonioideae in their 1975 monograph "On the Proteaceae: the evolution and classification of a southern family". They noted that it had large chromosomes, like those of Persoonia and allied genera, as well as sharing some other primitive features.

Description

Placospermum coriaceum trees grow to 30 m (100 ft) tall in their native rainforests, and are likely to be much smaller in cultivation. Leaves on the youngest plants are simple and oblanceolate, but large lobed intermediate leaves soon appear. These are up to 90 cm (36 in) long with up to nine lobes up to 20 cm (8 in) long each. The adult leaves are once again simple, and are spathulate or oblanceolate and up to 17 cm (7 in) long and leathery. The pinkish flowers grow in racemes at the end of branches. Flattened oval fruit follow, which measure 3.5-4 by 3 cm. Each contains many seeds. Like other members of the Persoonioideae, Placospermum coriaceum lacks the cluster roots typical of most Proteaceae. The large lobed immature leaves are an attractive feature, and Placospermum coriaceum has been cultivated as an indoor plant.

Distribution and habitat Placospermum coriaceum is endemic to the north-eastern tropical rainforest region of Queensland, Australia. It grows at a variety of altitudes ranging from 1,100 metres (3,600 ft) above sea level to at sea level. It is a locally common species that is not considered to be threatened and it is listed as 'Least concern' on the IUCN Red List of Threatened Species.

References

Illustrations

Worked examples

Example 1 — a first encounter with Placospermum

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

In research: Placospermum 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 Placospermum 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: Placospermum is common in secondary-school and first-year university syllabi. It links to neighbouring topics Endemic flora of Queensland, IUCN Red List least concern species, Least concern flora of Australia, so understanding it makes those chapters shorter.
In everyday life: Look for Placospermum 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 Placospermum in 20 minutes

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

Frequently asked questions

What is Placospermum in simple terms?

Why does Placospermum 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 Placospermum?

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 Placospermum.