Snake Cholla [Opuntia parryi Engelm. var. serpentina (Engelm.) L. Benson]

Snake Cholla [Opuntia parryi Engelm. var. serpentina (Engelm.) L. Benson]

Listing CNPS List 1B R-E-D Code 3-3-2

State/Federal. Status -- /C2 CACTACEAE Apr.-May

Global Rank G3T2 State Rank S1.1

Distribution: San Diego County; Baja California, Mexico

Habitat: Open Diegan Sage Scrub on xeric hillsides is the preferred habitat for this prostrate to suberect cane type cactus. Ferocactus viridescens, Mammillaria dioica, and Simmondsia chinensis may grow with this species. Soils include Huerhuero loam in Otay Valley, Gaviota fine sandy loam on Point Loma, and Redding cobbly loam in Balboa Park.

Known Sites: Scattered shrubs are found growing from Florida Canyon in Balboa Park to the Mexican border. Population densities are typically small. A good population is found on a hillside south of the Lower Otay camping area. An excellent population grows on the Subase at Point Loma, south of McClelland Road. Significant colonies are found on the northern slopes and bluffs of Poggi Canyon, and nearby close to Lynndale Lane in Chula Vista. Old biological survey reports note sites near Dillon Road on Otay Mesa, at the Otay Landfill, in Moody Canyon on Otay Mesa, near Glen Abbey Memorial Park in Bonita, and in Telegraph Canyon. Data Base reports are from several locales in Rice Canyon in Chula Vista, near San Ysidro, south of Otay Mesa Road and north of Moody Canyon, on a south-facing bank of Chollas Creek adjacent to Fairmont Avenue, and both 1.0 and 1.3 miles east of Rock Mountain in Otay Valley.

Five specimens are recorded for Baja Californica at the herbarium in the San Diego Natural History Museum; south to 31 5' North where collected by Moran (SD 106379) near Los Zaguaritos.It is occasional on a hill overlooking Rodriguez Dam, east of Tijuana, Mexico.

Status: Snake Cholla is substantially declining in San Diego County. This cacti is not often protected in situ when it occurs in areas of development, and is becoming quite rare. Mitigation plans sometimes call for moving cacti to newly cut slopes in artificial habitats where its long term establishment is suspect. Most known sites are endangered by development within the next 5-10 years. This plant is capable of being propagated and rooted from cuttings, and should be strongly considered for use on protected lands within its historical range. The prostrate growth habit of this species is quite distinct from variety parryi, from which it is geographically isolated. Herbarium material, not showing this trait, is similar and not readily differentiated. This variety is not recognized by Parfitt and Baker in their treatment of Opuntia in the Jepson Manual (1993); however, it is being retained in the CNPS listings. More taxonomic work is warranted. Provisionally, sizeable populations are recommended for protection. Smaller populations should be protected on-site within biological open space, or if necessary, transplanted to high quality native sage scrub habitat in dedicated biological open space.

Copyright May 1994 Craig H. Reiser.

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