science

Selenicereus undatus

Selenicereus undatus 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 Selenicereus undatus rather than just read about it. In short: Selenicereus undatus, the white-fleshed pitahaya, is a species of the genus Selenicereus (formerly Hylocereus) in the family Cactaceae and is the most cultivated species in the genus. It is used both as an ornamental vine and as a fruit crop, the pitahaya or dragon fruit.

Key takeaways

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

Reference excerpt

Selenicereus undatus, the white-fleshed pitahaya, is a species of the genus Selenicereus (formerly Hylocereus) in the family Cactaceae and is the most cultivated species in the genus. It is used both as an ornamental vine and as a fruit crop, the pitahaya or dragon fruit. Like all true cacti, the genus originates in the Americas. S. undatus is native from Mexico to Honduras; it may be a hybrid.

Description

Plant The stems are scandent (climbing habit), creeping, sprawling or clambering, and branch profusely. There can be four to seven stems, between 5 and 10 m (16 and 33 ft) or longer, with joints from 30 to 120 cm (12 to 47 in) or longer, and 10 to 12 cm (3.9 to 4.7 in) thick; with generally three ribs; margins are corneous (horn-like) with age, and undulate. Areoles, that is, the small area bearing spines or hairs on a cactus, are 2 mm (0.079 in) across with internodes 1 to 4 cm (0.39 to 1.57 in). Spines on the adult branches are 1 to 4 mm (0.039 to 0.157 in) long, being acicular (needle-like) to almost conical, and greyish brown to black in colour and spreading, with a deep green epidermis.

Flowers The scented, nocturnal flowers are 25 to 30 cm (9.8 to 11.8 in) long, 15 to 17 cm (5.9 to 6.7 in) wide with the pericarpel 2.5 to 5 cm (0.98 to 1.97 in) long, about 2.5 cm (0.98 in) thick, bracteoles ovate, acute, to 2.5 to less than 4 cm (1.6 in) long; receptacle about 3 cm (1.2 in) thick, bracteoles are linear-lanceolate, 3 to 8 cm (1.2 to 3.1 in) long; outer tepals lanceolate-linear to linear, acuminate (tapering to a point), being 10 to 15 cm (3.9 to 5.9 in) long, 10 to 15 mm (0.39 to 0.59 in) wide and mucronate (ending in a short sharp point). Their colour is greenish-yellow or whitish, rarely rose-tinged; these outer tepals, or sepals, are about 65 in number, and bring the flower to a total width of up to 35 cm (14 in). The inner tepals are lanceolate (tapering to a point at the tip) to oblanceolate (i.e. more pointed at the base), up to 10 to 15 cm (3.9 to 5.9 in) long about 40 mm (1.6 in) wide at widest point, and mucronate, unbroken, sharp to acuminate (pointed), and white.

Stamens 5 to 10 cm (2.0 to 3.9 in) long, are declinate, inserted in one continuous zone from throat to 35 mm (1.4 in) above the pericarpel and cream. The style (bearing the stigma) to 17, they are 5 to 24.5 cm (2.0 to 9.6 in) long, stout, 6 to 8 mm (0.24 to 0.31 in) thick, cream, and up to 26 stigma lobes, they can be whole or sometimes split at the top, cream, about 25 mm (0.98 in) long. Nectar chambers are 30 mm (1.2 in) long.

Fruit

The fruit is oblong to oval, 6 to 12 cm (2.4 to 4.7 in) long, 4 to 9 cm (1.6 to 3.5 in) thick, red with large bracteoles, with white, or more uncommonly, pink pulp and edible black seeds.

Habitat Selenicereus undatus is lithophytic or hemiepiphytic. It is widely distributed through the tropics in cultivation. It is a sprawling or vining, terrestrial or epiphytic cactus. They climb by use of aerial roots and can reach a height of 10 meters (33 feet) or more growing on rocks and trees.

Systematics This species is closely related to S. ocamponis and S. escuintlensis. Selenicereus undatus was described by (Haw.) Britton & Rose and published in Flora of Bermuda 256. 1918. In 2017, D. R. Hunt groups the genus Hylocereus within the genus Selenicereus. This has been supported by a phylogenetic analysis of the tribe Hylocereeae (Korotkova, et al., 2017), therefore this species is now treated under the name Selenicereus undatus

Taxonomy The species epithet undatus in Latin means "wavy" from unda "wave", referring to the wavy edges of its branch ribs.

Common names Czech: Dračí ovoce Danish: Dragefrugt English: pitahaya, dragon fruit, night blooming cereus, strawberry pear, Belle of the Night, Cinderella plant, Jesus in the cradle, moonflower Estonian: maasik-metskaktus Finnish: pitaija, lohikäärmehedelmä French: pitaya, fruit du dragon, cierge-lézard, poire de chardon German: Drachenfrucht, Distelbirne Greek: Φρούτο του δράκου (fruto tu draku) Hawaiian: panini-o-ka-puna-hou ("Punahou cactus") – a famous specimen still grows at Punahou School Japanese: pitaya (ピタヤ), dragon fruit (ドラゴンフルーツ), Korean: Yong-gwa (용과, 龍果, literal translation of dragon fruit), Portuguese: pitaia, cato-barse, cardo-ananaz, rainha da noite Spanish: pitahaya roja (Costa Rica, Colombia, Mexico, Venezuela); flor de caliz, pitajava (Puerto Rico); junco, junco tapatio, pitahaya orejona, reina de la noche, tasajo (Mexico) Swedish: skogskaktus, röd pitahaya Vietnamese: thanh long Thai: แก้วมังกร (kaeo mangkon) Malay: buah naga. pronounce:boo-ah naa-gaa Malayalam: വ്യാളീഫലം. Chinese: 火龙果, 火龍果; pinyin: huǒlóngguǒ Italian: Pitahaya, Frutto del Drago Bengali: ড্রাগন ফল (dragon fal) Lithuanian: kertuotis Myanmar: နဂါးမောက်သီး

See also Pitahaya List of culinary fruits

References

Anderson, E. F. (2001). The cactus family. Portland, Oregon, USA: Timber Press. ISBN 0-88192-498-9.

External links Media related to Selenicereus undatus at Wikimedia Commons Data related to Selenicereus undatus at Wikispecies Dragon fruit plant grower's tips, greenhouse, flower and more

Illustrations

Worked examples

Example 1 — a first encounter with Selenicereus undatus

Start with the simplest possible case. Write down what Selenicereus undatus 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 Selenicereus undatus 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 Selenicereus undatus 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 Selenicereus undatus

In research: Selenicereus undatus 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 Selenicereus undatus 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: Selenicereus undatus is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cacti of Mexico, Crops originating from Mexico, Crops originating from the Americas, so understanding it makes those chapters shorter.
In everyday life: Look for Selenicereus undatus 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 Selenicereus undatus in 20 minutes

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

Frequently asked questions

What is Selenicereus undatus in simple terms?

Why does Selenicereus undatus 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 Selenicereus undatus?

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 Selenicereus undatus.