science

Verbena bonariensis

Verbena bonariensis 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 Verbena bonariensis rather than just read about it. In short: Verbena bonariensis, commonly known as the purpletop vervain, clustertop vervain, Argentinian vervain, tall verbena or pretty verbena, is a member of the verbena family cultivated as a flowering annual or herbaceous perennial plant. In United States horticulture, it is also known by the ambiguous names purpletop (also used for the grass Tridens flavus) and South American vervain (which can mean any of the numerous s…

Key takeaways

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

Reference excerpt

Verbena bonariensis, commonly known as the purpletop vervain, clustertop vervain, Argentinian vervain, tall verbena or pretty verbena, is a member of the verbena family cultivated as a flowering annual or herbaceous perennial plant. In United States horticulture, it is also known by the ambiguous names purpletop (also used for the grass Tridens flavus) and South American vervain (which can mean any of the numerous species in the genus Verbena occurring on the continent). For the misapplication "Brazilian verbena", see below. It is native to tropical South America where it grows throughout most of the warm regions, from Colombia and Brazil to Argentina and Chile.

Description Verbena bonariensis is a tall and slender-stemmed perennial. It can grow to 6 ft (1.8 m) tall and can spread to 3 ft (0.91 m) wide. At maturity, it will develop a woody base. Fragrant lavender to rose-purple flowers are in tight clusters located on terminal and axillary stems, blooming from mid-summer until fall frost. The stem is square with very long internodes. Leaves are ovate to ovate-lanceolate with a toothed margin and grow up to 4 in (100 mm) long.

Etymology Verbena is derived from Latin, meaning ‘sacred bough’, in reference to the leafy twigs of vervaine (Verbena officinalis) which were historically carried by priests, used in wreaths for druidic rituals, and for medicine. Named by Virgil and Pliny the Elder. The common name, vervaine, comes from the Celtic name, ‘ferfain’. Its specific epithet bonariensis means 'from Buenos Aires, Argentina'. Buenos means 'good' and aires means 'air' ('good air'). All together, its name translates to "The sacred bough from the land of good air".

Taxonomy and systematics Verbena bonariensis is a member of the South American vervains, which are polyploid and have more than 14 chromosomes. Among these, it is part of a lineage which might also include Verbena intermedia and seems well distant from Verbena litoralis or Verbena montevidensis for example. Sometimes, the name Verbena brasiliensis, Brazilian verbena or Brazilian vervain, is found for this species. However, this is the result of a mix-up with V. brasiliensis, the "true" Brazilian verbena, which has been erroneously referred to as V. bonariaensis by several botanists.

Subspecies There are two named subspecies:

Verbena bonariensis subsp. bonariensis L. Verbena bonariensis subsp. conglomerata Briq.

Cultivation

V. bonariensis is cultivated as an ornamental plant for traditional and drought tolerant and 'pollinator-host' gardens and parks. It is a perennial, hardy in USDA Zones 7-11. It can be grown as an annual in areas where it is not winter hardy and will bloom in the first year when grown from seed. Its long internodes give it a sparse appearance but allow it to intermingle and coexist with other plants. The flowers, which appear in mid- to late summer, are very attractive to butterflies, and provide nectar for native bees and many beneficial garden insects. This species grows best in a well-drained soil. It prefers full sun to partial shade and needs regular moisture. It has a reputation of rarely being attacked by insect pests, but may be susceptible to powdery mildew. V. bonariensis is commonly grown from seed which germinates readily without pre-treatment, but can also be propagated from herbaceous stem cuttings. It has gained the Royal Horticultural Society's Award of Garden Merit.

Invasive species V. bonariensis self-seeds readily. This ability has raised concerns that it may become an invasive species and noxious weed in favorable habitats. It has naturalized in a number of southern United States. Presently, the plant is on the invasive species watchlist for Washington state, naturalized in tropical and southern Africa, temperate Asia, Australia, New Zealand, the United States (including Hawaii), the West Indies, Macaronesia and the Mascarene Islands. According to Pacific Island Ecosystems at Risk, it is considered a weed in Fiji, New Guinea and other South Pacific islands.

Footnotes

References Bailey, L.H. (1951): Verbena bonariensis. In: Manual of Cultivated Plants: 840. Macmillan Publishing Company. "Verbena bonariensis". Integrated Taxonomic Information System. Retrieved August 7, 2008. "Verbena bonariensis". Germplasm Resources Information Network. Agricultural Research Service, United States Department of Agriculture. Retrieved 2008-08-07. "Verbena brasiliensis". Germplasm Resources Information Network. Agricultural Research Service, United States Department of Agriculture. Retrieved 2008-08-07. United States Department of Agriculture (USDA) [2008b]: USDA Plants Profile: Verbena bonariensis. Retrieved 2008-AUG-07. Washington State Noxious Weed Control Board (WSNWCB) (2007): Tall Verbena, Purple Top, Cluster Flower Vervain. Version of 2007-MAR-31. Retrieved 2008-AUG-07. Yuan, Yao-Wu & Olmstead, Richard G. (2008): A species-level phylogenetic study of the Verbena complex (Verbenaceae) indicates two independent intergeneric chloroplast transfers. Molecular Phylogenetics and Evolution 48(1): 23–33. doi:10.1016/j.ympev.2008.04.004

External links

Missouri Botanical Garden Kemper Center for Home Gardening - Verbena bonariensis (Purpletop) Verbena bonariensis - Dr. Duke's Phytochemical and Ethnobotanical Database Pacific Island Ecosystems at Risk

Illustrations

Worked examples

Example 1 — a first encounter with Verbena bonariensis

Start with the simplest possible case. Write down what Verbena bonariensis 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 Verbena bonariensis 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 Verbena bonariensis 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 Verbena bonariensis

In research: Verbena bonariensis 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 Verbena bonariensis 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: Verbena bonariensis is common in secondary-school and first-year university syllabi. It links to neighbouring topics Botanical taxa named by Carl Linnaeus, Butterfly food plants, Drought-tolerant plants, so understanding it makes those chapters shorter.
In everyday life: Look for Verbena bonariensis 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 Verbena bonariensis in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Verbena bonariensis 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.
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Frequently asked questions

What is Verbena bonariensis in simple terms?

Why does Verbena bonariensis 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 Verbena bonariensis?

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 Verbena bonariensis.