The Pima Pineapple Cactus (Coryphantha scheeri var. robustispina) is a rare native plant of the Sonoran Desert. Its name comes from its primary distribution in Pima County, Arizona, and the pineapple-like appearance of its stem, with prominent knob-like sections. This cactus holds significant ecological value as a native species, representing a crucial component of the region’s biodiversity.
Identifying the Pima Pineapple Cactus
The Pima Pineapple Cactus is a small, typically globular to short-cylindrical cactus, often growing solitarily but sometimes forming clusters. It generally reaches 4 to 18 inches in height and 3 to 7 inches in diameter. A key identifying feature is its prominent tubercles, which are conical sections giving the cactus a bumpy, pineapple-like texture. Each tubercle bears an areole at its tip.
Its spination is also distinctive, featuring both radial and central spines. Each tubercle typically has 10-15 radial spines that are small and straight, surrounding one straw-colored, hooked central spine. The flowers are silky and yellow, blooming primarily in early July during the summer monsoon rains and continuing through August.
Following the bloom, the cactus produces sweet, green, oval-shaped fruit. The combination of its knob-like tubercles, specific spine arrangement, and summer blooming period with subsequent green fruit helps distinguish the Pima Pineapple Cactus from other cacti species.
Natural Environment and Distribution
The Pima Pineapple Cactus thrives in Sonoran Desert habitats. Its native range is highly restricted, primarily found in southeastern Arizona, particularly in Pima and Santa Cruz Counties, and extending into northern Sonora, Mexico.
This cactus prefers open, relatively flat areas, often on gently sloping alluvial fans, foothills of mountains, and valley floors. It grows in rocky, well-draining, sandy, and gravelly soils, typically at elevations ranging from 2,300 to 5,000 feet. Its flowering is synchronized with the onset of summer monsoons, which is crucial for reproduction.
The Pima Pineapple Cactus often coexists with other desert plants. The species relies heavily on specific ecological interactions, notably pollination by native, solitary, ground-nesting bees.
Conservation Status and Threats
The Pima Pineapple Cactus (Coryphantha scheeri var. robustispina) is federally recognized as an endangered species under the Endangered Species Act (ESA) since 1993, with only an estimated 1,500 individual cacti remaining in the United States. Its endangered listing is due to a combination of factors that threaten its survival and habitat.
Habitat loss and fragmentation represent the most significant threats to the Pima Pineapple Cactus. Extensive urban development, agricultural expansion, and the construction of border infrastructure in its limited range directly destroy and degrade its natural environment. These activities lead to the loss of topsoil and disrupt the delicate ecological balance necessary for the cactus’s survival. It is estimated that up to 75 percent of its current range could be lost due to urban development around Tucson.
Illegal collection poses another serious threat, as its rarity makes it a prized target for collectors. Climate change also impacts the species, with altered rainfall patterns and increased temperatures affecting its survival and reproduction. The proliferation of non-native grasses, such as Lehmann’s lovegrass, prevents new plants from establishing and alters fire frequencies. Predation by insects and small mammals, along with extended droughts, contribute to its vulnerability.
In response to these threats, the Pima Pineapple Cactus is protected under the ESA and is listed in CITES Appendix I. The U.S. Fish and Wildlife Service oversees its recovery efforts, focusing on habitat preservation and restoration. Conservation initiatives include the establishment of mitigation banks, such as the 590 acres set aside by the Pima County Board of Supervisors. Organizations like the Center for Biological Diversity have advocated for large-scale habitat conservation plans, such as the Sonoran Desert Conservation Plan, which aims to protect the Pima Pineapple Cactus and other endangered species. These efforts involve managing human development, monitoring populations, and implementing propagation programs and research initiatives to understand and protect the species.
Cultivation Considerations
Given its federally endangered status and highly specific environmental requirements, the Pima Pineapple Cactus is not a plant recommended for general home cultivation. Its survival in the wild depends on a complex interplay of soil composition, elevation, climate, and specific pollinator interactions that are exceedingly difficult to replicate outside its natural habitat.
The difficulty in mimicking its native Sonoran Desert conditions means most attempts at cultivation would likely fail and could encourage illegal collection. Any cultivation of the Pima Pineapple Cactus should only occur through legally and ethically sourced seeds or propagules from nurseries specializing in endangered species. Such instances often require specific permits from relevant authorities, like the U.S. Fish and Wildlife Service.
Instead of attempting to grow this rare cactus, a more responsible approach involves appreciating the Pima Pineapple Cactus within its natural environment. Supporting accredited conservation organizations and governmental agencies that are actively engaged in its protection and habitat restoration is a constructive way to contribute to its survival. These efforts help ensure the long-term viability of this unique Sonoran Desert species for future generations.