About Cereus forbesii C.F.Först.
Cereus forbesii C.F.Först. is a columnar, branching, colony-forming cactus. It can reach up to 3 meters (9 feet 10 inches) in height, with a mature circumference of around 15 centimeters (5.9 inches). However, due to weather, natural breakage, self-propagation, and other growth-limiting factors, it is most commonly seen growing to about 2 meters (6 feet 7 inches) tall. Larger recorded specimens have been observed exceeding 7 meters (23 feet) in height. Its cylindrical shoots are initially blue-green, turning light green as they mature, and measure 5 to 8 centimeters in diameter. The columnar stems have 4 to 8 blunt, compressed ribs. The areoles are small and gray. A single strong, yellowish-brown central spine is most common, though specimens occasionally develop two or three; this central spine can grow up to 16 centimeters (6.3 inches) long. Five radial spines surround the central spine, reaching up to 2 centimeters (0.79 inches) in length. The flowers of this species range from white to reddish, and often have pink outer petals and a yellow center. After pollination, blooms develop into red, pulpy fruits that are similar to the fruits of some Opuntia species. This cactus is endemic to Argentina, where it occurs in the provinces of Catamarca, Chaco, Córdoba, Formosa, Jujuy, La Rioja, Salta, Santa Fe, Santiago del Estero, Tucumán, and the area north of the city of San Luís. In Bolivia, it is found in the departments of Chuquisaca, Santa Cruz, and Tarija. It grows on arid, windswept hills, in sparse forests, on wooded plains, and along the edges of salt flats, most commonly at elevations between 500 and 2,000 meters (1,600 and 6,600 feet). Like its close relatives, Cereus forbesii is adapted to extreme temperature fluctuations, including full sun exposure during the day and seasonal near-freezing nighttime temperatures, especially in winter. Plants growing above 2,000 meters above sea level may even experience winter snowfall.
