CPC Plant Profile: Cochise Pincushion Cactus
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Plant Profile

Cochise Pincushion Cactus (Escobaria robbinsorum)

The cochise foxtail cactus, shown growing in pots at the Desert Botanical Garden. Photo Credit:
Description
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: Federally Threatened
  • Family: Cactaceae
  • State: AZ, MX, SI
  • Nature Serve ID: 158625
  • Date Inducted in National Collection: 02/10/1987

Small (1.0-1.5 cm) above ground, unbranched cactus, 1.4-6.0 cm wide. This diminutive globular cactus is covered with tiny, grooved tubercules (Hunt 1978). Each tubercule has an areole filled with long white trichomes, and 11-17 radial spines (Earle 1963). A deep furrow can be seen on the upper portion of each tubercule. Central spines are usually lacking. One to three slender spines may be present on the upper portion of the aereole. The pale yellow-green, bell-shaped flowers (10-18.5 mm long, 12-20 mm in diameter), occur in early spring (Lopresti 1984). Fruits are small and globular, red in color, eventually drying on the plants. There are about 20 blobular black seeds in each fruit. The bright white radial spines and small size distinguish it from any other cactus in the area. When mature, these cacti are smaller than any other cactus species in the area. The spines are so dense, the stems cannot generally be seen. C. vivipara var. bisbeeana occurs in the same habitat but does not have cottony aereoles and has central spines that are differentiated. The two taxa need to be seen together in order to make a positive identification.

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Updates
Katie Heineman
  • 06/23/2022
  • Living Collection

Arizona Sonora Desert Museum has wild provenance living collections of this species maintained in an ex-situ greenhouse setting.

  • 09/10/2020
  • Living Collection

During 1999, DBG received 33 plants, each approximately 2 cm in diameter, from a private individual. These plants immediately flowered at the time they normally would have, and controlled cross-pollinations were conducted, producing 78 fruits and a total of 2827 seeds.

  • 09/10/2020
  • Reproductive Research

The failure to germinate seeds collected from any of the plants, provided support to the idea that freezing may not be appropriate for some seeds of desert plants, notably members of Cactaceae. Experimentation with some other species of cactus has provided similar results. The protocol for the storage process for Cactaceae is being re-examined at Desert Botanical Garden (DBG). Another collection was made from the same site during 1995. Five seeds were collected from each of 50 plants. During 1999, DBG received 33 plants, each approximately 2 cm in diameter, from a private individual. These plants immediately flowered at the time they normally would have, and controlled cross-pollinations were conducted, producing 78 fruits and a total of 2827 seeds. The seeds were allowed to dry in the partially dry fruits, and then cleaned and counted by hand. They were stored in an airtight foil pouch after 6 weeks of drying at 63 degrees C. Germination tests have been conducted, resulting in 64% germination. Approximately 30 seedlings remain alive from this experiment. They are approximately 1 mm in diameter at 6 months old, and have developed the first two to three spine clusters.

  • 09/10/2020
  • Propagation Research

The first collection was made in 1987 when 812 seeds were collected. The seeds appeared immature at the time of collection, and germination tests failed. The seeds had been immediately frozen following cleaning and counting, prior to establishing a baseline germination percentage. If the seeds were not fully mature, it is possible that freezing killed the developing embryos. The failure to germinate seeds collected from any of the plants, provided support to the idea that freezing may not be appropriate for some seeds of desert plants, notably members of Cactaceae. Experimentation with some other species of cactus has provided similar results. The protocol for the storage process for Cactaceae is being re-examined at Desert Botanical Garden (DBG). Another collection was made from the same site during 1995. Five seeds were collected from each of 50 plants. During 1999, DBG received 33 plants, each approximately 2 cm in diameter, from a private individual. These plants immediately flowered at the time they normally would have, and controlled cross-pollinations were conducted, producing 78 fruits and a total of 2827 seeds. The seeds were allowed to dry in the partially dry fruits, and then cleaned and counted by hand. They were stored in an airtight foil pouch after 6 weeks of drying at 63 degrees C. Germination tests have been conducted, resulting in 64% germination. Approximately 30 seedlings remain alive from this experiment. They are approximately 1 mm in diameter at 6 months old, and have developed the first two to three spine clusters.

  • 09/10/2020
  • Orthodox Seed Banking

Seedbanking for this species calls into question the protocol for establishing a conservation seedbank, as each plant may produce only 1200 seeds during its lifetime. Until germination tests provide more definite results, the Garden maintains a conservative approach to augmenting the seedbank it has established. Desert Botanical Garden has only 2 field seed collections, both obtained from a population occurring on privately owned land. The first collection was made in 1987 when 812 seeds were collected. The seeds appeared immature at the time of collection, and germination tests failed. The seeds had been immediately frozen following cleaning and counting, prior to establishing a baseline germination percentage. If the seeds were not fully mature, it is possible that freezing killed the developing embryos. The protocol for the storage process for Cactaceae is being re-examined at Desert Botanical Garden (DBG). Another collection was made from the same site during 1995. Five seeds were collected from each of 50 plants.

  • 09/10/2020
  • Seed Collection

Seedbanking for this species calls into question the protocol for establishing a conservation seedbank, as each plant may produce only 1200 seeds during its lifetime. Until germination tests provide more definite results, the Garden maintains a conservative approach to augmenting the seedbank it has established. Desert Botanical Garden has only 2 field seed collections, both obtained from a population occurring on privately owned land. The first collection was made in 1987 when 812 seeds were collected. The seeds appeared immature at the time of collection, and germination tests failed. The seeds had been immediately frozen following cleaning and counting, prior to establishing a baseline germination percentage. If the seeds were not fully mature, it is possible that freezing killed the developing embryos. The protocol for the storage process for Cactaceae is being re-examined at Desert Botanical Garden (DBG). Another collection was made from the same site during 1995. Five seeds were collected from each of 50 plants.

Nature Serve Biotics
  • 05/02/2017

Despite intensive searching, this species is known only from 1 population in southeastern Arizona and 1 in adjacent Sonora, Mexico. Most of the plants are concentrated in small pockets of this tiny range, making the species especially vulnerable to cactus poachers; also potentially threatened by pesticides and mining.

Kathleen C. Rice
  • 01/01/2010

The major threat to this species lies in its limited range and the scarcity of plants within that range. It would take only a small localized catastrophic event to decimate the species, or reduce its numbers to a point where it could no longer sustain its

Kathleen C. Rice
  • 01/01/2010

Only three populations of this species are known in the US. All are located within walking distance from each other (USFWS 1993). A detailed census covering one square hectare was completed by Zimmerman (1978), who found approximately 470 plants.

Kathleen C. Rice
  • 01/01/2010

The failure to germinate seeds collected from any of the plants, provided support to the idea that freezing may not be appropriate for some seeds of desert plants, notably members of Cactaceae. Experimentation with some other species of cactus has provided similar results. The protocol for the storage process for Cactaceae is being re-examined at Desert Botanical Garden (DBG). Another collection was made from the same site during 1995. Five seeds were collected from each of 50 plants. During 1999, DBG received 33 plants, each approximately 2 cm in diameter, from a private individual. These plants immediately flowered at the time they normally would have, and controlled cross-pollinations were conducted, producing 78 fruits and a total of 2827 seeds. The seeds were allowed to dry in the partially dry fruits, and then cleaned and counted by hand. They were stored in an airtight foil pouch after 6 weeks of drying at 63 degrees C. Germination tests have been conducted, resulting in 64% germination. Approximately 30 seedlings remain alive from this experiment. They are approximately 1 mm in diameter at 6 months old, and have developed the first two to three spine clusters.

Kathleen C. Rice
  • 01/01/2010

Populations are located on privately owned, state and BLM land.

Kathleen C. Rice
  • 01/01/2010

In its recovery plan for this species, the USFWS (1993) outlined management and restoration needs that include: creating a management plan, studying population biology and aspects of reproductive biology and ecology, protecting habitat through law enforcement, protection from pesticides, establishing new populations, and seed banking.

Kathleen C. Rice
  • 01/01/2010

Seedbanking for this species calls into question the protocol for establishing a conservation seedbank, as each plant may produce only 1200 seeds during its lifetime. Until germination tests provide more definite results, the Garden maintains a conservative approach to augmenting the seedbank it has established. Desert Botanical Garden has only 2 field seed collections, both obtained from a population occurring on privately owned land. The first collection was made in 1987 when 812 seeds were collected. The seeds appeared immature at the time of collection, and germination tests failed. The seeds had been immediately frozen following cleaning and counting, prior to establishing a baseline germination percentage. If the seeds were not fully mature, it is possible that freezing killed the developing embryos.

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Photos
Nomenclature
Taxon Escobaria robbinsorum
Authority (W.H. Earle) D.R. Hunt
Family Cactaceae
CPC Number 1086
ITIS 907934
USDA ESRO
Common Names cochise foxtail cactus | Cochise pincushion cactus
Associated Scientific Names Coryphantha robbinsorum | Escobaria robbinsorum | Escobaria robbinsiorum (orthographic variant) | Cochiseia robbinsiorum | Coryphantha robbinsiorum (orthographic variant)
Distribution Populations are 'bunched', occurring in groups, or sub-populations within the species' range (USFWS 1993). Plants tend to be solitary or scattered in discrete sub-populations rather than randomly spr
State Rank
State State Rank
Arizona S1
Mexico S1
Sonora S1
Habitat

The habitat is an unnamed range of hills comprised of limestone, broken into broad sheets, interspersed with patches of desert pavement (Schmalzel et al. 1995). The general vegetation is a transition between Chihuahuan Desert Scrub and semi-desert Grassland. Elevation is about 4,200-4,650 feet (USFWS 1993). Surrounding species include Fouquieria splendens, Vaquelinia pauciflora, Larrea tridentata, Prosopis velutina, Rhus microphylla, Rhus coriophylla, Agave palmeri, and Dasyliron wheeleri (USFWS 1986, 1993).

Ecological Relationships

C. robbinsorum is an obligate outcrosser, pollinated by two species of tiny, native bees (Zimmerman 1978). Flowers are visited by small native bees (Perdita opuntiae and Ashmeadiella opuntiae) while seeds may be dispersed by rock wrens, cactus wrens, black throated sparrows, thrashers and house finches (Zimmerman 1978).During dry seasons, plants lose enough water to 'shrink' down to ground level, virtually disappearing among the spaces between the rocky substrate. Seedlings are almost impossible to find. Speculation as to the ultimate lifespan of Coryphantha robbinsorum varies from 18 to 40 years. The difficulty in estimating ages of plants lies in the very slow growth (ca 1-2 mm/year in diameter). Plants begin flowering in late March and early April. Fruiting occurs from the thrid week of June through the third of fourtheweek of August. Seeds soll down the mother plant and germinate beneath it. Short distance dispersal of seeds and fruit is year-round, long distance dispersal is June through August. Flowers and fruits are produced annually if pollination and fertilization are successful. Seeds germinate at unknown intervals following fruit maturation, repeating the cycle (USFWS Register 1985).

Pollinators
Common Name Name in Text Association Type Source InteractionID
Bees
Leaf-cutting bees Ashmeadiella opuntiae Floral Visitor Link
Sweat bees Dialictus Floral Visitor Link
Mining bees Perdita opuntiae Floral Visitor Link
Reintroduction
Lead Institution State Reintroduction Type Year of First Outplanting

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