Mature cacti vary in height from three to nine inches. The spines consist of two to three purplish central spines and twelve radial spines. The central spines point upward.1 The flowers range from pink to purple in color. The fruits are pale green.2 The flowers have been observed to be pollinated by at least ten species of native bees.3
The Acuña cactus is found on well-drained knolls and gravel ridges at 1,3002,000 feet elevation in the Sonoran desert scrub.
Historically, the cactus was found in Pinal, Pima, and possibly Maricopa Counties in Arizona, and in Sonora, Mexico. Currently, there are four known populations in Arizona.
The Acuña cactus is a candidate species for the Threatened and Endangered list. The plant is protected by the Arizona Native Plant Law, and is protected for international trade by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). 1
The Acuña Cactus in Pima County:
Of the four known populations in Arizona1, three occur in Pima County on federal, state, and private lands. Organ Pipe National Monument has the largest and healthiest known population.3 The population may be threatened by illegal take1 and natural causes such as parasitism.3 A population may occur on Barry M. Goldwater Gunnery Range.1
1. U.S. Fish and Wildlife Service. 1992. Handbook of Arizona's Endangered, Threatened, and Candidate Plants. U.S.FWS, Phoenix, Arizona. pp. 30.
2. Arizona Game and Fish Department. 1997. Echinomastus erectocentrus var. acunensis. Heritage Data Management System.
3. Johnson, R.A. 1992. "Pollination and reproductive ecology of acuña cactus, Echinomastus erectocentrus var. acunensis. Int. J. Plant Science 153(3):400-408. Heritage Data Management System.
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