Plants in the cactus family, Cactaceae, originated in North, Central, and South America. They are widely distributed, from coastal areas, to high mountains, and in tropical rainforests. Their appearance is just as variable, from thimble-size species, to enormous column species, and the epiphytic (climbing) species. The yellow pitaya was probably Selenicereus megalanthus, and the red pitaya, Hylocereus ocamponis or Hylocereus undatus. Cereus triangularis is a synonym of Hylocereus undatus.

Hylocereus undatus (Haworth) Britt & Rose, a climbing cactus thought to be from the tropical rainforests of Central and northern South America, is one species that has been used as a food source. It has already received world-wide recognition as an ornamental plant for the large, scented, night-blooming flowers. Its fame is now spreading throughout the world for its fruit, especially in Israel, Vietnam, and Australia.

Other climbing cactus species grown for the edible fruit include Hylocereus polyrhizus and Selenicereus megalanthus. H. polyrhizus has red skin and red flesh dotted with edible black seeds, while S. megalanthus, the pitaya amarillo or yellow pitaya, has yellow skin and clear to white flesh containing edible black seeds. Columnar cacti, such as Cereus peruvianus - the apple cactus, and the shrubby Opuntia species - the cactus (prickly) pears, are also grown for their edible fruit.

Freshly cut stems and flowers of Selenicereus grandiflorus, in particular, are used in the preparation of drugs which have a spasmolytic effect on the coronary vessels and promote blood circulation. For this purpose, cuttings are cultivated in hot-houses.


Origin

North, Central, and South America

Foliage

Reduction or absence of leaves

Flowers

In warm climates, the dry season is when active growth slows or stops. H. undatus flowers are self-compatible, producing fruit with one species, but cross-pollination with other Hylocereus species can produce larger fruit. H. undatus is a long-day plant, requiring longer day lengths to induce flowering. In the Northern Hemisphere, the main fruiting season occurs between May to October. Recent observations suggest the season in Darwin may extend from October to April.

Buds are contained in aerioles along the three-ribbed stem and emerge in the summer months. Once emerged, the buds then form into branches or flowers. The scented, white, night-blooming flowers attract bats and moths. Bees and other insects visit the flowers before dusk as the petals open, and after dawn as the flowers begin to close.

Fruits

Ten days after flower opening, fruitset is visible. Fruit development is rapid. After a further 25 days, the fruit is ready to be harvested. Fruit can be left on the stem up to 15 days at this stage. The average fruit weight is 350 grams and this increases with the number of seeds present. The flowers and fruit can be thinned to 1-2 fruit per branch, to produce fruit of an even size and quality for the export market.

Food Uses

The ripe strawberry pear is much appreciated, especially if chilled and cut in half so that the flesh can be eaten with a spoon. The juice is enjoyed as a cool drink. A sirup made of the whole fruit is used to color pastries and candy. The unopened flowerbud can be cooked and eaten as a vegetable.

Food Value

We have only Aguilar Giron's assay of the pulp: water, 92.20; protein, 0.48-0.50; carbohydrates, 4.33-4.98; fat, 0.17-0.18; fiber, 1.12; ash, 1.10%.

Info Source : International Tropical Fruits Network