Selenicereus undatus

Dragonfruit stems are scandent (climbing habit), creeping, sprawling or clambering, and branch profusely. There can be four to seven of them, 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.[3]

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 grayish brown to black in colour and spreading, with a deep green epidermis.[3]

• 
  Segment
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  Plant

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 fourteen inches (35 centimeters).[5] 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.

• 
  Flower bud
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  Blooming flower
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  In bloom in Kona, Hawaii.

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.[3]

Mature fruits

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.[3]

The species's epithet undatus in Latin means "wavy" from unda "wave",[7] referring to the wavy edges of its branches' ribs.

S. undatus shoots overlooking Lanikai and Na Mokulua, Oahu, Hawaii.

• Czech: Dračí ovoce
• Dansk: Dragefrugt
• English: pitahaya, dragon fruit, night blooming cereus, strawberry pear, Belle of the Night, Cinderella plant, Jesus in the cradle, moonflower[8]
• 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