Hylocereus megalanthus is a cactus

Cactus

A cactus is a member of the plant family Cactaceae. Their distinctive appearance is a result of adaptations to conserve water in dry and/or hot environments. In most species, the stem has evolved to become photosynthetic and succulent, while the leaves have evolved into spines...

 species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 native to northern South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

, where it is known, along with its fruit, by the name of Pitahaya

Pitaya

A pitaya or pitahaya is the fruit of several cactus species, most importantly of the genus Hylocereus . These fruits are commonly known as dragon fruit – cf...

. The species is grown commercially for its fruit, but is also an impressive ornamental vine with perhaps the largest flowers of all cacti

Cacti

-See also:* RRDtool The underlying software upon which Cacti is built* MRTG The original Multi Router Traffic Grapher from which RRDtool was "extracted".* Munin -External links:******...

.

Etymology

Megalanthus (Greek) - large flowered. This species produces among of the largest flowers within the cactus family.

Common Names

• English: Yellow Pitahaya
• German: Gelbe Pitaya, Gelbe Pitahaya
• Swedish: gul pitahaya

Origin and habitat

Venezuela

Venezuela

Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...

 to Peru

Peru

Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....

, including Colombia

Colombia

Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...

, Bolivia

Bolivia

Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...

, Ecuador

Ecuador

Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...

, in tropical Riparian forests. It is Epiphytic or xerophytic.

Description

• Stems may lie along the ground (procumbent), climb (scandent), or hang (pendent). Stems are often only 1.5 cm thick, producing areoal roots; 3 ribs; margins slightly undulating; white areole
  Areole
  Areoles are an important diagnostic feature of cacti, and identify them as a family distinct from other succulent plants. The areoles on cacti are clearly visible; they generally appear as small light- to dark-colored bumps, out of which grow clusters of spines...
  
  s; 1-3 spines 2-3 mm long, yellowish; several hairs on young growth, britle-like; green epidermis
  Epidermis (botany)
  The epidermis is a single-layered group of cells that covers plants' leaves, flowers, roots and stems. It forms a boundary between the plant and the external environment. The epidermis serves several functions, it protects against water loss, regulates gas exchange, secretes metabolic compounds,...
  
  . *Flowers are nocturnal and funnel-shaped, 32-38 cm long; pericarpel is ovoid or slightly globose, tubercles are large and flattened, with felt-like and spiny areoles subtended by small bracteoles; receptacle elongate; outer tepals long, green, triangular-acute; inner tepals 100 cm long, 3.5 cm wide, white, broader; stamens numerous inserted in two zones, yellow; style yellow, stigma lobes numerous, green.
• Fruit: ovoid, tuberculate, spiny, yellow (or sometimes red?), seeds black; interior edible, having a pleasant, mildly sweet flavor.

Systematics

Closely related to Hylocereus setaceus

Hylocereus setaceus

Hylocereus setaceus is a species of plant in the Cactaceae family. It is found in Argentina, Bolivia, Brazil, and Paraguay. Its natural habitats are subtropical or tropical dry forests, subtropical or tropical moist lowland forests, rocky shores, and sandy shores. It is threatened by habitat...

(floral tube or pericarpel 19-22 cm with small tubercles) but otherwice quite isolated within Hylocereus. Is intermediate between Selenicereus and Hylocereus

Hylocereus

Hylocereus is a genus of cacti, often referred to as nightblooming cactus . Several species have large edible fruits, which are known as pitaya or dragonfruits.-Taxonomy:...

. Recent research suggest that this species originated as a hybrid between species of Hylocereus

Hylocereus

Hylocereus is a genus of cacti, often referred to as nightblooming cactus . Several species have large edible fruits, which are known as pitaya or dragonfruits.-Taxonomy:...

 and Selenicereus (see references). The two species possibly involved, as being native in the same area, are Hylocereus costaricensis

Hylocereus costaricensis

Hylocereus costaricensis, the Costa Rica Pitahaya, is a cactus species native to Central America and northwestern South America. The species is grown commercially for its Pitaya fruit, but is also an impressive ornamental vine with huge flowers. Most plants grown under the name Hylocereus...

 and Selenicereus inermis.

Cultivation

An easily cultivated, fast growing plant. Needs a compost containing plenty of humus and sufficient moisture in summer. Should not be kept under 8ºC (46,5ºF) in winter. Can be grown in semi-shade, but best in full sunlight. Extra light in the early spring will stimulate budding. Flowers in June to October. This plant may grow to a very large size.