biology

Nassella

Nassella 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 Nassella rather than just read about it. In short: Nassella, or needlegrass, is a New World genus of over 100 perennial bunchgrasses found from North America through South America. The Latin word nassa refers to "a basket with a narrow neck".

Key takeaways

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

Reference excerpt

Nassella, or needlegrass, is a New World genus of over 100 perennial bunchgrasses found from North America through South America. The Latin word nassa refers to "a basket with a narrow neck". It is usually considered segregate from the genus Stipa and includes many New World species formerly classified in that genus. As of 2011, The Jepson Manual includes Nassella within Stipa. Nasella is characterized by strongly overlapping lemma margins and reduced, veinless paleae. The lemma tips are fused into the "crown", a short membrane that surrounds the base of the lemma. The rim of the crown usually has hairs. Many species form both cross-pollinating and self-pollinating florets in the terminal panicle. The self-pollinating florets have 1–3 small anthers; the cross-pollinating florets have 3 longer anthers. Some species have self-pollinating inflorescences hidden in their basal leaf sheaths. These hidden inflorescences lack glumes and usually lack awns. Some species, especially Nassella neesiana and Nassella tenuissima, are considered invasive pests, as the grass is not properly digested by ruminants.

Diversity As of 2001, there were about 116 species in this genus.

California species Nassella pulchra – purple needlegrass; currently reclassified as Stipa pulchra. A native grass of California that was once a dominant species in California grasslands before invasive European grasses became dominant. The seeds were an important food source for many of the Indigenous peoples of California. Today, the bunchgrass is the State Grass of California and plays an important role in native grassland restoration and erosion control. Nassella lepida – foothill needlegrass; currently reclassified as Stipa lepida. A native bunchgrass of California and Baja California. Nassella cernua – nodding needlegrass; currently reclassified as Stipa cernua. A native bunchgrass of California, Northwestern Mexico, and the Western United States.

Horticultural species Nassella tenuissima – Mexican feathergrass. An attractive, drought-tolerant bunchgrass with fine leaves and a narrow inflorescence that sways gracefully in the wind. However, it readily escapes from cultivation and takes hold in disturbed areas, natural areas, and in sidewalk cracks, driveways, and tree wells. It is an invasive species in California and Oregon.

Other species Nassella charruana (Arechav.) Barkworth Nassella chilensis – Chilean tussockgrass Nassella crassiflora (Roseng. & B.R.Arrill.) Barkworth Nassella hyalina – spear grass Nassella ibarrensis Nassella laevissima Nassella leucotricha – Texas wintergrass Nassella manicata – Andean tussockgrass, tropical needlegrass Nassella neesiana – Chilean needle grass Nassella rosengurttii (Chase) Barkworth Nassella trichotoma – serrated tussockgrass, Yass River tussockgrass Nassella viridula – green needlegrass

References

External links Calflora Database: Nassella Flora of North America, Grass Manual: Nassella

Illustrations

Worked examples

Example 1 — a first encounter with Nassella

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

In research: Nassella 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 Nassella 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: Nassella is common in secondary-school and first-year university syllabi. It links to neighbouring topics Bunchgrasses of North America, Bunchgrasses of South America, Drought-tolerant plants, so understanding it makes those chapters shorter.
In everyday life: Look for Nassella 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 Nassella in 20 minutes

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

Frequently asked questions

What is Nassella in simple terms?

Nassella, or needlegrass, is a New World genus of over 100 perennial bunchgrasses found from North America through South America. The Latin word nassa refers to "a basket with a narrow neck".

Why does Nassella 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 Nassella?

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 Nassella.