Hylocereus megalanthus

Taxobox
name = Yellow Pitaya

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image_width = 240px
image_caption = Photo: Edward
regnum = Plantae
divisio = Magnoliophyta
classis = Magnoliopsida
ordo = Caryophyllales
familia = Cactaceae
subfamilia = Cactoideae
tribus = Hylocereeae
genus = "Hylocereus"
species = "H. megalanthus"
binomial = "Hylocereus megalanthus"
binomial_authority = (K. Schumann ex Vaupel) Ralf Bauer (2003) Cactaceae Syst. Init. 17: 28
synonyms =
"Cereus megalanthus" K. Schumann ex Vaupel (1913) Notizbl. Bot. Gart. Berlin-Dahlem 5:284
"Mediocactus megalanthus" (K. Schumann ex Vaupel) Britton & Rose Cact. 2:210
"Selenicereus megalanthus" (K. Schumann ex Vaupel) Moran (1953) Gentes Herb. 8:325

"Hylocereus megalanthus" is a cactus species native to northern South America. The species is grown commercially for its fruit, but is also an impressive ornamental vine with perhaps the largest flowers of all cacti.

Common Names

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

Etymology

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

Origin and habitat

Colombia to Peru, Bolivia Ecuador and Venezuela. Riverine forests. Epiphytic or xerophytic.

ystematics

Closely related to "Hylocereus setaceus" but otherwice quite isolated within "Hylocereus". Is intermediate between "Selenicereus" and "Hylocereus". Recent research suggest that this species originated as a hybrid between species of Hylocereus and Selenicereus (see references). The two species possibly involved, as being native in the same area, are Hylocereus costaricensis 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 sun. Extra light in the early spring will stimulate budding. Flowers in june to October. This plant grow very large.

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 areoles; 1-3 spines 2-3 mm long, yellowish; several hairs on young growth, britle-like; green epidermis. 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.some are poison
*"Hylocereus megalanthus" - floral tube or pericarpel 30-38 cm long with large flattened tubercles.
*"Hylocereus setaceus" - floral tube or pericarpel 19-22 cm with small tubercles.

References

*Anderson, E. F. (2001). The Cactus Family. Timber Press ISBN 0-88192-498-9
*Bauer, R. (2003) A synopsis of the tribe Hylocereeae F. Buxb. Cactaceae Syst. Init. 17: 3-63.
*Tel-Zur N, Abbo S, Bar-Zvi D, Mizrahi Y. (2004 ) Genetic relationships among Hylocereus and Selenicereus vine cacti (Cactaceae): evidence from hybridization and cytological studies. Ann Bot (Lond) 94(4):527-34.