Regularity: Regularly occurring
Global Range: It occurs in Arizona (east Pinal, Graham, east Pima, Santa Cruz and Cochise Cos. and scattered localities in mountains just above the desert in Yuma, Yavapai, Maricopa, and west Pima Cos.), New Mexico (east to Otero Co.), Texas (Franklin Mts.), and likely in Mexico.
Catalog Number: US 1821083
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Original publication and alleged type specimen examined
Preparation: Pressed specimen
Collector(s): C. R. Orcutt
Year Collected: 1922
Locality: Maricopa, Arizona, United States, North America
- Type collection: Britton, N. L. & Rose, J. N. 1923. Cactaceae. 4: 156.
Habitat and Ecology
Comments: It occurs on hills and washes in grassland. In the Whipple Mountains in southeastern California, it is found on igneous gravelly slopes and rocky hillsides. It frequently grows in the shade of burrobush or paloverde, but also occurs in open areas with desert barrel cactus and buckhorn cholla (Ingram 2008).
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: 21 - 80
Comments: Fifty EO's (Benson 1982).
Seedlings of this species will common establish under nurse plants, avoiding full exposure to harsh desert environmental elements.
Life History and Behavior
Mammillaria grahamii is predominately an outcrossing species. In a greenhouse experiment, only 10% of self-pollinated plants set fruit and none of the seeds from the selfed fruit germinated (Bowers 2002). Mammillaria is dispersed by a wide array of vertebrate animals (van Rheede van Ousdtshorn and van Rooyen 1999). Vertebrates have more motility and are expected to generally travel longer distances than invertebrates. Mammillaria grahamii has a long-term, persistent seedbank. Seedbanks can represent an additional adaptation or 'hedge' when environmental conditions are not suitable for reproduction in some years (Bowers 2005).
IUCN Red List Assessment
Red List Category
Red List Criteria
Mammillaria grahamii is wide-ranging, abundant, and there are no known threats. Hence, it is listed as Least Concern.
National NatureServe Conservation Status
Rounded National Status Rank: NNR - Unranked
NatureServe Conservation Status
Rounded Global Status Rank: G4 - Apparently Secure
Reasons: Rank of G4 from Texas Heritage Program (3/94).
Comments: Most cacti subject to horticultural collecting.
- "PLANTS Profile for Mammillaria grahamii". USDA Plants Database. USDA. Retrieved 17 April 2013.
- "Mammillaria grahamii". Lady Bird Johnson Wildflower Center. Retrieved 17 April 2013.
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All spine hooks on a plant may be oriented in the same direction, a trait sometimes mistakenly said to be limited to Mammillaria mainiae. Plants with short, straight central spines (rarely a mixture of both hooked and straight spines on the same stem) occur in some populations; they have been called M. oliviae or M. grahamii var. oliviae. The name Mammillaria microcarpa Engelmann has been widely used but was not validly published until after M. grahamii.