science

Stipule

Stipule is a science 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 Stipule rather than just read about it. In short: In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole). They are primarily found among dicots and rare among monocots.

Key takeaways

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

Reference excerpt

In botany, a stipule is an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole). They are primarily found among dicots and rare among monocots. Stipules are considered part of the anatomy of the leaf of a typical flowering plant, although in many species they may be inconspicuous —or sometimes entirely absent, and the leaf is then termed exstipulate. At the other end of the scale are species like Artocarpus elasticus where the stipules can be up to eight inches (twenty cm) in length. (In some older botanical writing, the term "stipule" was used more generally to refer to any small leaves or leaf-parts, notably prophylls.) The word stipule was coined by Linnaeus from Latin stipula, straw, stalk.

Types of stipules

General characteristics The position of stipules on a plant varies widely from species to species, though they are often located near the base of a leaf. Stipules are most common on dicotyledons, where they appear in pairs alongside each leaf. Some monocotyledon plants display stipule-like structures, but only display one per leaf. A relationship exists between the anatomy of the stem node and the presence or absence of stipules: most plants with trilacunar nodes have stipules; species with unilacunar nodes lack stipules. Stipules are morphologically variable and might appear as glands, scales, hairs, spines, or laminar (leaf-like) structures. If a single stipule goes all the way around the stem, it is known as an ochrea.

Types

According to duration The three types of stipules according to duration are caducous, deciduous and persistent. Caducous stipules fall off before the leaf unfolds, while deciduous stipules fall off immediately after the leaf unfolds. Persistent stipules remain attached to the plant.

According to shape, size and position Stipules can be considered free lateral, adnate, interpetiolar, intrapetiolar, ochreate, foliaceous, bud scales, tendrillar or spiny. A stipule can be fused to the stem, or to the other stipule from the same node. A stipule is "adnate" if it's fused together on part of the petiole length, but the anterior is still free. A stipule is "interpetiolar" if it is located in between the petioles, as opposed to being attached to the petioles, and generally one stipule from each leaf is fused together, so it appears that there's just one stipule between each leaf. A stipule is "intrapetiolar" if it is located in the angle that is between a stem and a petiole. In this case, the two stipules generally form together and appear to be one stipule. A stipule is "ochreate" if a single stipule appears to be a solid tube that goes all the way around the stem. A stipule is "foliaceous" if it is leaf-like. These are generally used to photosynthesize. A stipule is considered a "bud scale" if it is hard or scaly and protects leaf buds as they form. These generally fall off as soon as the leaf unfolds. A stipule is considered "tendrillar" if they are long thin tendrils, and are generally used by climbing plants. A stipule is considered "spiny" if they are long and pointy. These are generally used to deter animals. A stipule is considered to be "abaxial", "counter" or "leaf opposed" if it is located on the opposite side to where the leaf meets the stem.

Purpose of stipules Stipules have various functions. Some stipules are not well understood or may be vestigial. It is known that foliaceous stipules are used like leaves to make energy for the plants. Sometimes stipules protect the next leaf or bud as it grows in then falls off after the leaf unfolds, as with Tulip Poplars. Stipules can be used as climbing tendrils by climbing plants. Spiny stipules can be used to help protect the plant from animals.

References

General references Esau, K. 1953. Plant Anatomy. Second Edition. John Wiley & Sons, Inc., New York, London, Sidney. 767 pp.

External links Stipules and stipels

Illustrations

Worked examples

Example 1 — a first encounter with Stipule

Start with the simplest possible case. Write down what Stipule claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Stipule 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 Stipule 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 Stipule

In research: Stipule appears in science 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 Stipule 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: Stipule is common in secondary-school and first-year university syllabi. It links to neighbouring topics Leaf morphology, so understanding it makes those chapters shorter.
In everyday life: Look for Stipule 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 Stipule in 20 minutes

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

Frequently asked questions

What is Stipule in simple terms?

Why does Stipule matter?

Because it connects several science 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 Stipule?

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 Stipule.