Harrisia (applecactus and moonlight cactus) is a genus of night blooming cacti.
They are tree-shaped, sometimes climbing or shrub-like cacti with cylindrical shoots. They reach heights of up to 7 m. The shoots are ribbed (four to twelve ribs) and do not form aerial roots. The flowers open at night, are white and up to 12 cm in diameter. After successful pollination, rounded fruits are formed, which are red to orange in color. The fruits have scales with areoles in the axils. The black seeds are 2 to 3 ÃÂ 1.5 mm in size.
Plants are native to Argentina, Paraguay, Brazil, Bolivia, Uruguay, the Greater Antilles, the Bahamas, and the U.S. state of Florida. The genus is named after William Harris, an important botanist of Jamaica. There are about 20 species.
Harrisia cactus is an exotic invasive in Australia in Queensland and New South Wales, in Africa, and in the U.S. state of Hawaii.
The genus was established by Nathaniel Lord Britton in 1909.
, Plants of the World Online accepted the following species separated into two subgenera: