biology

Grammitis

Grammitis 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 Grammitis rather than just read about it. In short: Grammitis (dwarf polypody) is a genus of ferns in the family Polypodiaceae, subfamily Grammitidoideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I). It had formerly been placed in the family Grammitidaceae, but this family is no longer recognized by most authors because phylogenetic analyses of DNA sequences have shown that it is embedded in Polypodiaceae.

Key takeaways

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

Reference excerpt

Grammitis (dwarf polypody) is a genus of ferns in the family Polypodiaceae, subfamily Grammitidoideae, according to the Pteridophyte Phylogeny Group classification of 2016 (PPG I). It had formerly been placed in the family Grammitidaceae, but this family is no longer recognized by most authors because phylogenetic analyses of DNA sequences have shown that it is embedded in Polypodiaceae. The delimitation of Grammitis was drastically narrowed in the first decade of the 21st century. It now contains about 25 species. In 2003, a study of the distribution of grammitid ferns placed 11 species in the New World, 7 in Africa, and 4 in the Pacific. The genus Grammitis was established by Olof Swartz around 1801. (sources vary on the exact date). The name is derived from Greek, gramma, grammatos meaning "a line or thread" and refers to the arrangement of the sori in some species. The type species for Grammitis is Grammitis marginella. The only known fossil of a grammitid fern has been named Grammitis succinea, but it is not clear that it belongs to Grammitis as more recently defined. It was found in Oligocene amber from the Dominican Republic.

Circumscription In a treatment of Grammitidaceae in 1990, Barbara S. Parris defined Grammitis broadly, to include about 400 species. At that time, she stated that "The treatment of Grammitis here as a large and diverse genus reflects our current lack of knowledge concerning relationships within the family". Other authors at that time circumscribed Grammitis more narrowly, to include about 200 species. Since about 2003, Grammitis has been understood as a genus of about 25 species with the other species to be eventually transferred to other genera, most of them new or resurrected. Grammitis sensu strictissimo (about 25 species) is distinguished by its black, sclerified leaf margins. It is sister to the monophyletic genus Cochlidium. In 2004, Grammitis was shown to be polyphyletic if broadly circumscribed. Grammitis tenella had been shown to be closely related to Adenophorus in 2003, and the new combination Adenophorus tenellus was published in 2008. Several species formerly in Grammitis have been transferred to Oreogrammitis. These include Oreogrammitis clemensiae, Oreogrammitis hookeri, and others. The genera Ctenopterella, Dasygrammitis, Radiogrammitis, Tomophyllum, and Xiphopterella were established in 2007 and some of these contain species that were formerly in Grammitis. Lellingeria tomensis was moved out of Grammitis to Lellingeria in 2004. Transfers to other genera have also been made. The classification of Grammitis basalis, Grammitis recondita, and others remains undecided. Plants of the World Online circumscribes Grammitis broadly, with 700 species and 56 generic synonyms.

Species The species list is incomplete and may contain synonyms. It was originally based on two very old sources.

Transferred species

References

External links

Schrader's Journal für die Botanik CRC World Dictionary of Plant Names: D-L — At: Botany & Plant Science; At: Life Science At: CRC Press

Illustrations

Worked examples

Example 1 — a first encounter with Grammitis

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

In research: Grammitis 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 Grammitis 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: Grammitis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Fern genera, Grammitis, Taxa described in 1801, so understanding it makes those chapters shorter.
In everyday life: Look for Grammitis 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 Grammitis in 20 minutes

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

Frequently asked questions

What is Grammitis in simple terms?

Why does Grammitis 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 Grammitis?

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 Grammitis.