Marshallia

Key takeaways

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

Reference excerpt

Marshallia is a genus of plants in the tribe Helenieae within the family Asteraceae. Marshallia is native to the southeastern and south-central United States. A common name applied to most species in the genus is Barbara's buttons.

Description Marshallia is found in open habitats, such as roadsides, bogs, or open woodlands dominated by pines. Several species are associated with wetlands. The typical blooming period is late spring (May) and early summer (June or early July). The small white-to-pinkish flowers occur in large, compact, spherical heads Marshallia are very attractive to pollinating insects, including butterflies and various beetles, such as flower chafers of the genus Euphoria.

Species Marshallia angustifolia (Michx.) Pursh - TN Marshallia caespitosa Nutt. ex DC., puffballs. - TX OK KS MO AR LA Marshallia graminifolia (Walt.) Small, grassleaf Barbara's buttons. - TX LA MS AL GA FL SC NC †Marshallia grandiflora Beadle & F.E. Boynt., Appalachian Barbara's buttons. - NC Marshallia legrandii Weakley, tall Barbara's buttons. - NC, VA Marshallia mohrii Beadle & F.E. Boynt, Mohr's Barbara's buttons. - AL GA Marshallia obovata (Walt.) Beadle & F.E. Boynt. spoonshape Barbara's buttons. - TN AL GA FL SC NC VA Marshallia pulchra W.M. Knapp, D.B. Poind. & Weakley beautiful Barbara’s buttons. - TN KY WV MD PA Marshallia ramosa Beadle & F.E.Boynt., southern Barbara's buttons. - FL GA Marshallia trinervia (Walt.) Trel., broadleaf Barbara's buttons. - LA MS AL GA SC NC TN

Conservation One species in the genus, Marshallia grandiflora (Appalachian Barbara's buttons) is extinct, having been wiped out in the early 20th century. It was formerly considered conspecific with Marshallia pulchra (Beautiful Barbara's buttons or Monongahela Barbara's buttons), which is endangered in Kentucky, Pennsylvania, and Tennessee, and has been extirpated in Maryland. That species is found in bogs and scoured riverbanks, and requires periodic flooding to maintain open habitat. Marshallia obovata (Spoonshape Barbara's buttons or Piedmont Barbara's buttons), is listed as endangered in Florida and threatened in Tennessee.

Etymology The genus name was given by the botanist Schreber (in Genera Plantarum, 1791) to honor the Marshall family, uncle Humphry and nephew Moses, of Pennsylvania. They were botanists of the American colonial period, and cousins of the famous botanists and explorers John and William Bartram. The origin of the common name "Barbara's buttons" is unknown. The flower heads do resemble buttons, but botanical references giving this name do not quote the Barbara which the name honors (Rickett 1975). The reference is possibly to Saint Barbara, though the association is obscure. Saint Barbara had long hair, and is also associated with lightning—perhaps the individual flowers resemble lightning bolts, or the whole head of flowers resembles Saint Barbara's long locks (Coin 2005). This common name was not, at any rate, widespread in the 19th century. It was not used in Southern Wildflowers and Trees (1901) or Plant Life Of Alabama (1901). The botanist B.W. Wells, in Natural Gardens of North Carolina (1932), called the plants "loudspeakers", referring to the megaphone shape of the individual flowers. The first printed use of the name "Barbara's buttons" is in Small's Manual of the Southeastern Flora (1933).

References

Further reading Channell, Robert Bennie (1955). A revisional study of the genus Marshallia Schreb (Compositae). Thesis (Ph. D.) Duke University. Duncan, Wilbur H., Marion B. Duncan (1999). Wildflowers of the Eastern United States. University of Georgia Press. ISBN 0-8203-2107-9. Lounsberry, Alice (1901). Southern Wild Flowers and Trees. New York: Frederick A. Stokes Company. Mohr, Charles T. (1901). Plant Life Of Alabama. Montgomery, Alabama: Brown Printing Company. Porcher, Richard D., Douglas A. Rayner (2002), A Guide to the Wildflowers of South Carolina. University of South Carolina Press. ISBN 1-57003-437-0. Radford, Albert E., H.E. Ahles, and C. R. Bell (1968). Manual of the Vascular Flora of the Carolinas. Chapel Hill, North Carolina: University of North Carolina Press. ISBN 0-8078-1087-8. Rickett, Harold (1975). Wildflowers of the United States II(2): 630. New York: McGraw-Hill. Small, John Kunkel (1933). Manual of Southeastern Flora. Chapel Hill: University of North Carolina Press. Wells, B.W. (1932, reprint 2002). Natural Gardens of North Carolina. Chapel Hill: University of North Carolina Press. ISBN 0-8078-4993-6. Center for Plant Conservation account for Marshallia grandiflora, accessed 25 May 2006

External links USDA Plants Profile: Marshallia Media related to Marshallia at Wikimedia Commons

Illustrations

Worked examples

Example 1 — a first encounter with Marshallia

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

In research: Marshallia 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 Marshallia 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: Marshallia is common in secondary-school and first-year university syllabi. It links to neighbouring topics Asteraceae genera, Endemic flora of the United States, Flora of the Southeastern United States, so understanding it makes those chapters shorter.
In everyday life: Look for Marshallia 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.

How to study Marshallia in 20 minutes

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

Frequently asked questions

What is Marshallia in simple terms?

Marshallia is a genus of plants in the tribe Helenieae within the family Asteraceae. Marshallia is native to the southeastern and south-central United States.

Why does Marshallia 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 Marshallia?

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 Marshallia.