Common Name(s): Senita

Family: Cactaceae

Native To: Southern Arizona, Baja California and Sonora, Mexico

Native Habitat: Wash borders, silty flats and rocky hillsides

Growth Habit: Upright, multi-stemmed cactus

Flowering: April to August (night-blooming)

Distinguishing Characteristics: This columnar cactus has many stems, up to 8 in wide and 15 ft high; branching is from the base. Each stem has 5-10 ribs. Upper sections of adult stems produce spine clusters (areoles) with 15-50 bristle-like, gray spines 1-4 in long. These are very different from the short-spined lower portions of the stem. Flowers are produced mostly from the upper stems. Pale pink flowers, 1 ½ in wide, open after dark and close around dawn. They are pollinated by a small moth specialized to live its life cycle on this cactus. The fruits reach 1 ½ inch in diameter and are spineless, red, and fleshy when mature.

Natural History and Cultivation Notes: The genus name, Pachycereus, means "crested cereus" and the species, schottii, is in honor of Arthur Schott (1814-1875) who worked with the Mexico Boundary Commission as a plant collector. Like many other cacti, these plants have numerous spines. Spines presumably provide protection from herbivores but are also thought to shade the delicate green photosynthesising surface of the plant, protecting it from sun burn. They also direct water droplets down to the base of the plant, which is maybe an efficient way to harvest water in the foggy coastal desert of Baja. A bizarre mutant form of Senita, called the Totem Pole cactus, essentially lacks spines and has smooth knobby irregular stems. This form occurs in Baja California and is sometimes cultivated as an ornamental in Arizona.

Ethnobotany: The fruits can be eaten fresh. The Seri used the wood to build various forms of shelter and houses. The Seri believe the Senita to have a very powerful spirit, given by the spirit of vegetation, Icor. The spirit of the Senita was consulted for placing curses that would eventually lead to sickness and death of an enemy.

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