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Witch-hazel

Witch-hazel 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 Witch-hazel rather than just read about it. In short: Witch-hazels or witch hazels (Hamamelis) are a genus of flowering plants in the family Hamamelidaceae, with three species in North America (H. ovalis, H. virginiana, and H. vernalis), and one each in Japan (H. japonica) and China (H. mollis). The North American species are occasionally called winterbloom.

Witch-hazel — main illustration
Witch-hazel — illustration

Key takeaways

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

Reference excerpt

Witch-hazels or witch hazels (Hamamelis) are a genus of flowering plants in the family Hamamelidaceae, with three species in North America (H. ovalis, H. virginiana, and H. vernalis), and one each in Japan (H. japonica) and China (H. mollis). The North American species are occasionally called winterbloom.

Description The witch-hazels are deciduous shrubs or (rarely) small trees growing to 3 to 7.5 m tall, even more rarely to 12 m tall. The leaves are alternately arranged, oval, 5 to 15 cm long, and 2.5 to 10 cm wide, with a smooth or wavy margin. The genus name, Hamamelis, means "together with fruit", referring to the simultaneous occurrence of flowers with the maturing fruit from the previous year. H. virginiana blooms in September–November while the other species bloom from January–March. Each flower has four slender strap-shaped petals 1 to 2 cm long, pale to dark yellow, orange, or red. The fruit is a two-part capsule 1 cm long, containing a single 0.6 cm glossy black seed in each of the two parts; the capsule splits explosively at maturity in the autumn about eight months after flowering, ejecting the seeds with sufficient force to fly for distances of up to 12 feet (3.7 m), thus another alternative name "snapping hazel".

Etymology The name witch in witch-hazel has its origins in Middle English wiche, from the Old English wice, meaning "pliant" or "bendable", and is not related to the word witch meaning a practitioner of magic. Jacob George Strutt's 1822 book, Sylva Britannica attests that "Wych Hazel" was used in England as a synonym for wych elm, the entirely unrelated Ulmus glabra. The use of the twigs as divining rods, just as hazel twigs were used in England, may also have, by folk etymology, influenced the "witch" part of the name.

Species Five species are recognized:

Hamamelis japonica Siebold & Zucc. – Japanese witch-hazel Hamamelis mollis Oliv. – Chinese witch hazel Hamamelis ovalis S.W.Leonard – big-leaf witch-hazel Hamamelis vernalis Sarg. – Ozark witchhazel Hamamelis virginiana L. – common witch-hazel or American witch-hazel Hamamelis mexicana is sometimes considered a species, though as of 2020 Kew's Plants of the World Online considers it a variety of H. virginiana. The Persian ironwood, a closely related tree formerly treated as Hamamelis persica, is now given a genus of its own, as Parrotia persica, as it differs in the flowers having just sepals and no petals. Other closely allied genera are Parrotiopsis, Fothergilla, and Sycopsis (see under Hamamelidaceae). Witch-hazels are not closely related to the true Corylus hazels, though they have a few superficially similar characteristics which may cause one to believe that they are - their leaves are a similar shape, and turn a similar shade of yellow in autumn.

Cultivation They are popular ornamental plants, grown for their clusters of rich yellow to orange-red flowers, which begin to expand in the autumn as or slightly before the leaves fall and continue throughout the winter.

Garden shrubs Hamamelis virginiana was introduced into English gardens by Peter Collinson, who maintained correspondence with plant hunters in the American colonies. It is rarely seen in the nursery trade except for woodland/wildlife restoration projects and native plant enthusiasts. Much more common is H. mollis, which has bright yellow flowers that bloom in late winter instead of the yellow blossoms of H. virginiana which tend to be lost among the plant's fall foliage. The plant-hunter Charles Maries collected for Veitch Nurseries in the Chinese district of Jiujiang in 1879. It languished in nursery rows for years until it was noticed, propagated, and put on the market in 1902. Numerous cultivars have been selected for use as garden shrubs, many of them derived from the hybrid H. × intermedia Rehder (H. japonica × H. mollis). Jelena and Robert de Belder of Arboretum Kalmthout, selecting for red cultivars, found three: the first, with bronze flowers, was named 'Jelena'; the next, with red flowers, was named 'Diane' (the name of their daughter); the last, with deep red flowers, was called 'Livia' (the name of their granddaughter).

Phytochemicals and hamamelis water The main phytochemicals in witch-hazel leaves are polyphenols, including 3–10% tannins, flavonoids, and up to 0.5% essential oil, while the bark has a higher tannin content. Hamamelis water, also called white hazel or witch hazel water prepared from a steam-distillation process using leaves, bark or twigs, is a clear, colorless liquid containing 13–15% ethanol having the odor of the essential oil, but with no tannins present. Essential oil components, such as carvacrol and eugenol, may be present. As an ingredient and topical agent, witch-hazel water is regulated in the United States as an over-the-counter drug for external use only to soothe minor skin irritations. Hamamelis (witch-hazel) water is diluted using water in a 1:3 preparation, and is not intended for oral use which may cause nausea, vomiting, or constipation.

Topical ointment Witch-hazel may be sold as a semisolid ointment, cream, gel, or salve for topical use, and due to its astringent and antiseptic properties, has long been used to treat various skin conditions like acne. The ointment may ease discomfort from post-partum vaginal soreness and hemorrhoids. It is commonly used to treat diaper rash in infants, and may reduce symptoms of inflammation from minor skin injuries. A 2012 review (updated in October 2020) found little evidence of effectiveness from local cooling treatments (including witch-hazel pads) applied to the perineum following childbirth to relieve pain.

… excerpt ends here. Continue reading the full article.

Illustrations

Witch-hazel illustration
Witch-hazel illustration
Witch-hazel illustration
Witch-hazel illustration
Witch-hazel illustration

Worked examples

Example 1 — a first encounter with Witch-hazel

Start with the simplest possible case. Write down what Witch-hazel 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 Witch-hazel 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 Witch-hazel 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 Witch-hazel

In research
Witch-hazel 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 Witch-hazel 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
Witch-hazel is common in secondary-school and first-year university syllabi. It links to neighbouring topics Antihemorrhagics, Hamamelidaceae, Medicinal plants, so understanding it makes those chapters shorter.
In everyday life
Look for Witch-hazel 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 Witch-hazel in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Witch-hazel means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Witch-hazel out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Witch-hazel in simple terms?

Witch-hazels or witch hazels (Hamamelis) are a genus of flowering plants in the family Hamamelidaceae, with three species in North America (H. ovalis, H. virginiana, and H. vernalis), and one each in Japan (H. japonica) and China (H. mollis). The North American species are occasionally called winte…

Why does Witch-hazel 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 Witch-hazel?

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 Witch-hazel.

Tags

  • Antihemorrhagics
  • Hamamelidaceae
  • Medicinal plants
  • Traditional medicine

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