Saguaro, Sahuaro . American cacti plant up to 18m high, with a lone trunk with branches like arms and white flowers that open only at night to give a red fruit.
- Cereus giganteus Engelm.
- Pilocereus engelmannii Lem.
- Pilocereus giganteus Rumpler 
Origin: United States , in the state of Arizona; and of Mexico , in the state of Sonora.Carnegiea is a genus that has only one species: Carnegiea gigantea, of common name Saguaro.The stem is columnar and can reach a height of 15 m and a diameter of 65 cm. The plant has ramifications and can be found in a number greater than 8. Radial spines can be 12 or more, and central ones between 3 and 6 of up to 7 cm in length. They are colored brown and gray go back as the plant ages.
Flower color white waxy, about 12 cm long and diameter nearly that dimension. Green Exterior , with scales on the pericarp and in the tube. Stamens very numerous with yellow antennae. Cream white stigma with 15 lobes. Flowering is in spring. They open during the night and remain open part of the following day. The fruit is red and edible. Matures in summer.
Very slow growth. It takes 30 years to reach 1 m in height and subsequently its growth rate is about 2.5-3 cm per year in the mainstem. The maximum speed that can reach in some vigorous ramification is of about 10 cm per year. The largest specimens that exist in the Arizona desert can be 200-300 years old.
The national flower of the state of Arizona (USA) is the one of this species. In Tucson (Arizona), a large area densely populated by this species was dedicated by the government of the United States as a biological reserve, receiving the name of Saguaro National Monument
Light: sun, in the case of large specimens, but a slight shadow in the case of young specimens. Large thermal differences, typical of deserts , are observed: minimum temperatures of -9 ° C. up to more than 50 ° C. Temperatures: the recommended minimum for young specimens is about 5ºC. Regarding grown specimens we have references that can withstand -9ºC. Winter at 5ºC.
Normal irrigation in the growing period, which comprises fewer months than in the case of the other cacti . In the rest of the year it needs less water than the average of the cactus. Standard composite substrate. It needs a large pot since the roots expand considerably.
Multiplication by seed . It is autoésteril, which means that the pollen of a specimen is not able to fertilize its flowers . The pollination cross between different samples is carried out in the habitat bees , some birds and a type of bat .
The cross pollination between different specimens is carried out, in the biotope , by bees , some birds and a type of bat (Leptonycteris) .
The saguaro has been since times remote very important part in the economy and tradition of losindígenas the desert , particularly the Papago . Their trunks usually serve as material for the construction of houses, while both their flowers and their fruits , rich in sugars , and their seeds are edible. From the red pulps of the fruits a syrup is prepared , and sometimes also a wine that is usually used in a ritual ceremony in the rain .