biology

Ophioglossum

Ophioglossum 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 Ophioglossum rather than just read about it. In short: Ophioglossum, the adder's-tongue ferns, is a genus of about 50 species of ferns in the family Ophioglossaceae. The genus name comes from Ancient Greek ὄφις (óphis), meaning "snake", and γλῶσσα (glôssa), meaning "tongue".

Key takeaways

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

Reference excerpt

Ophioglossum, the adder's-tongue ferns, is a genus of about 50 species of ferns in the family Ophioglossaceae. The genus name comes from Ancient Greek ὄφις (óphis), meaning "snake", and γλῶσσα (glôssa), meaning "tongue". Their cosmopolitan distribution is mainly in tropical and subtropical habitats. The genus has the largest number of chromosomes in the known plant kingdom, but contrary to popular belief does not have the largest number of chromosomes out of all known organisms, falling short to the protist Sterkiella histriomuscorum.

Description Adders-tongues are so-called because the spore-bearing stalk is thought to resemble a snake's tongue. Each plant typically sends up a small, undivided leaf blade with netted venation, and the spore stalk forks from the leaf stalk, terminating in sporangia which are partially concealed within a structure with slit sides. When the leaf blade is present, there is not always a spore stalk present, and the plants do not always send up a leaf, sometimes going for a year to a period of years living only under the soil, nourished by association with soil fungi. The plant grows from a central, budding, fleshy structure with fleshy, radiating roots. Ophioglossum malviae is known as the world's smallest terrestrial fern.

Polyploidy Ophioglossum has a high chromosome count in comparison to other species, with 120 or up to 720 chromosomes possible in intervals of 120 due to polyploidy (multiple possible copies of chromosomes). It has almost 1260 number of chromosomes in the meiocyte (spore mother cell) which undergo meiosis, the reduction division to form the spore with only one set of chromosomes getting incorporated into each spore. The species Ophioglossum reticulatum has the highest number of chromosomes found in any multicellular organism.

Taxonomy The Smith et al. classification of 2006, based on molecular phylogeny, placed Ophioglossum in Ophioglossaceae. Subsequent classifications have maintained this placement. Circumscriptions of the genus vary. The Christenhusz and Chase classification of 2014 includes Cheiroglossa and Ophioderma within Ophioglossum. This circumscription corresponds to subfamily Ophioglossoideae in the PPG I classification, which recognizes Cheiroglossa, Ophioderma, and Rhizoglossum as separate genera. More recently, it has been proposed to subdivide Ophioglossum more narrowly, removing a number of species into the new genera Goswamia, Haukia, and Whittieria.

Phylogeny Phylogeny of Ophioglossum

Unassigned species:

References

External links Flora of North America: Ophioglossum (Adder's-tongue)

Illustrations

Worked examples

Example 1 — a first encounter with Ophioglossum

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

In research: Ophioglossum 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 Ophioglossum 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: Ophioglossum is common in secondary-school and first-year university syllabi. It links to neighbouring topics Botanical taxa named by Carl Linnaeus, Fern genera, Ophioglossaceae, so understanding it makes those chapters shorter.
In everyday life: Look for Ophioglossum 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 Ophioglossum in 20 minutes

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

Frequently asked questions

What is Ophioglossum in simple terms?

Why does Ophioglossum 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 Ophioglossum?

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 Ophioglossum.