Hylocereus megalanthus

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iYellow Pitaya

Photo: Edward

Scientific classification

Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Caryophyllales
Family:	Cactaceae
Subfamily:	Cactoideae
Tribe:	Hylocereeae
Genus:	Hylocereus
Species:	H. megalanthus

Binomial name

Hylocereus megalanthus
(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.

1 Common Names
2 Etymology
3 Origin and habitat
4 Systematics
5 Cultivation
6 Description
7 References

[edit] Common Names

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

[edit] Etymology

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

[edit] Origin and habitat

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

[edit] Systematics

Closely realted to Hylocereus setaceus but otherwice quite isolated within Hylocereus. Is intermediate between Selenicereus and Hylocereus. Recent reseach suggest that this species orginated as a hybrid between species of Hylocereus and Selenicereus (see references). The two species possible involved, as being native in the same area, are Hylocereus costaricensis and Selenicereus inermis.

[edit] 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.

Fruit, spines removed

[edit] Description

Stems procumbent, scandent or pendent, often only 1,5 cm thick, producing areoal roots; ribs 3; margins slightly undulating; areoles white; spines 1-3, 2-3 mm long, yellowish; hairs several on young growth, britle-like; epidermis green. Flowers funnelform, 32-38 cm long, nocturnal; pericarpel ovoid or slightly globose, tubercles large and flattened, with felt-like and spiny areoles subtended vy small bracteoles; receptacle elongate,; outer tepals long, triangular-acute., green; 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.

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.

[edit] 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.