(DRAFT) - Taxonomy
                          Species CACTUS, PINCUSHION, SILER
                                Species Id ESIS702018
                                   Date 13 MAR 96



TAXONOMY

NAME - CACTUS, PINCUSHION, SILER OTHER COMMON NAMES - CACTUS, PINCUSHION, SILER; CACTUS, SILVER; CACTUS and GYPSUM ELEMENT CODE - CATEGORY - Angiosperm PHYLUM AND SUBPHYLUM - MAGNOLIOPHYTA, CLASS AND SUBCLASS - MAGNOLIOPSIDA, ORDER AND SUBORDER - CARYOPHYLLALES, FAMILY AND SUBFAMILY - CACTACEAE, GENUS AND SUBGENUS - PEDIOCACTUS, SPECIES AND SSP - SILERI, SCIENTIFIC NAME - PEDIOCACTUS SILERI AUTHORITY - TAXONOMY REFERENCES - COMMENTS ON TAXONOMY - Siler Pincushion Cactus Pediocactus sileri (Engelmann) L. Benson KINGDOM: Plant GROUP: Angiosperm DIVISION: Magnoliophyta CLASS: Magnoliopsida ORDER: Caryophyllales FAMILY: Cactaceae Pediocactus sileri is a small, solitary, globose cactus, about 10 cm (4 inches) tall and 7.5 to 10 cm (3 to 4 inches) in diameter. Gierisch and Anderson (16) give a maximum size of 45 cm (18 inches) tall. There are 3 to 7 brownish-black (becoming gray to white with age) straight spines per circular areole. There are in addition, 11 to 16 whitish radial spines per areole. The central spines are about 2.5 cm (1 inch) long, the radials slightly less. The flowers are about 2.5 cm in diameter and are yellowish with maroon veins. The greenish-yellow fruits have scales, are enlarged upward, and are dry at maturity; the scales are gray (03,06,07,17,19). Siler pincushion cactus was described by Engelmann in 1896 in Coulter (11), based on specimens collected by A.L. Siler in May of 1883 at Cottonwood Springs and Pipe Springs. Engelmann did not have the fruit so the taxon was included in Echinocactus. Two type locations were given in the original citation, one of which was Taxonomy - 1 (DRAFT) - Taxonomy Species CACTUS, PINCUSHION, SILER Species Id ESIS702018 Date 13 MAR 96 probably in Utah, and the other in Arizona (25). Britton and Rose (08) applied the generic name Utahia because of its supposed location in Utah, but for many years its presence there was open to question (01,03,19,31). It is today known from Utah near St. George, Washington County (28) and near Kanab, Kane County (14, 15), as well as Arizona. Lyman Benson (03,04,05) placed the species in the genus Pediocactus, section Pediocactus, along with P. simpsonii, P. knowltonii, P. paradinei, and P. bradyi. Although there are many dissimilarities between the species placed in Pediocactus, Benson recognized the overriding similarity: the structure and method of dehiscence of the fruit. The dull-colored dry fruits open along a vertical slit in the ovary wall and fold back, with the top opening like a lid (03,17). Backeberg (02) continued using the name Utahia, separating the taxon from Pediocactus based on floral characteristics. However, most taxonomists accept Benson's placement of the taxon as Pediocactus sileri (17). The type specimen is located at the Missouri Botanical Garden, MO (03,17). A photograph of the type is located at the New York Botanical Garden NY (03). There are many published descriptions of the species (03,06,07,09,11,17,19,22,23,24,28,31). The most complete and accurate original descriptions are those of Peebles (19), Benson (03,06,07), and Heil et al. (17). Many publications have photographs of the species and its habitat (01,06,07,14,15,16,17,18,19,31). Drawings occur in publications (09, 28) and at the USFWS, Regional Office in Albuquerque, NM. Specimens have been deposited at the Missouri Botanical Garden, Brigham Young University, Desert Botanical Garden, Museum of Northern Arizona, Navajo Community College, Pomona College, University of AZ, University of NM, and the University of UT. Taxonomy - 2
                                  (DRAFT) - Status
                          Species CACTUS, PINCUSHION, SILER
                                Species Id ESIS702018
                                   Date 13 MAR 96



STATUS

Coded Status E: Federal Endangered Commercial Non-consumptive recreational Ornamental COMMENTS ON STATUS - U.S. STATUSES AND LAWS: The siler pincushion cactus (Pediocactus sileri) has been designated an Endangered species pursuant to the Endangered Species Act of 1973 (50 CFR 17.12; P.L. 93-205, 87 Stat. 884; 16 U.S.C. 1531-1540), as amended. The species has this status wherever found including the States of Arizona and Utah. Removal and reduction to possession of any Federally listed plant from an area under Federal jurisdiction is unlawful (50 CFR 17.61 and 17.71). This species is protected by the Lacey Act (P.L. 97-79, as amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to possess any wild plant (including roots, seeds, and other parts) within U.S. territorial or special maritime jurisdiction (as defined in 18 U.S.C. 7); or to import, export, transport, sell, receive, acquire, or purchase in interstate or foreign commerce any wild plant (including roots, seeds, and other parts) taken, possessed, transported, or sold in violation of any State law or regulation. It is also unlawful to import, export, transport, sell, receive, acquire, or purchase any wild plant (including roots, seeds, and other parts) taken or possessed in violation of any U.S. law, treaty, or regulation or in violation of Indian tribal law. RESPONSIBLE FEDERAL AGENCIES: USFWS -Responsible for the management/recovery, listing, and law enforcement/protection of this species. BIA -Responsible for the law enforcement/protection of this species with applicable State and Federal laws on public lands under their control. Also responsible for management/recovery on Bureau of Indian Affairs lands. BLM -Responsible for the law enforcement/protection of this species with applicable State and Federal laws on public land under their control (43 CFR 4140). Also responsible for management/recovery on Bureau of Land Management lands. All Federal agencies have responsibility to ensure that any Status - 1 (DRAFT) - Status Species CACTUS, PINCUSHION, SILER Species Id ESIS702018 Date 13 MAR 96 action authorized, funded, or carried out by that agency is not likely to jeopardize the continued existence of the species or result in the destruction or adverse modification of Critical Habitat (50 CFR 402), and to utilize their authorities to carry out programs for the conservation of the species. STATE STATUSES AND LAWS: STATE: Utah DESIGNATED STATUS: None STATE: Arizona DESIGNATED STATUS: Protected ADMINISTRATIVE AGENCY: Arizona Commission of Agriculture and Horticulture STATE STATUTE: Arizona Revised Statutes, Chapter 7, Sec 3-901B INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS: This species is listed in Appendix I of CITES. ECONOMIC STATUSES: This species has horticultural value and is commercially available from cactus and succulent dealers. It's rarity makes it particularly desirable to collectors. It has value as a component of Arizona and Utah's natural heritage of biotic diversity. 75/07/01:40 FR 27823/27924 - Notice of review 76/06/16:41 FR 24523/24572 - Proposed Endangered 79/11/26:44 FR 61786/61788 - Listing as Endangered 85/07/22:50 FR 29901/29909 - Five year review Status - 2
     

HABITAT ASSOCIATIONS

HABITAT - TERRESTRIAL TERRESTRIAL LAND USE - Shrub and Brush Rangeland COMMENTS ON HABITAT ASSOCIATIONS - Pediocactus sileri is generally found on gypsiferous and calcareous clay soils mostly derived from various members of the Triassic Age Moenkopi Formation. It is sometimes found on nearly identical-appearing members of the Chinle and Kaibab Formations, above and below the Moenkopi, respectively (13,14,15,16,22,23). The soils apparently are high in soluble salts and are usually white, although they occasionally are red if derived from one of the red members of the Moenkopi Formation (14,15,23). Soil texture varies from very gravelly or shaley sandy loam through fine sandy loam to clay loam. In some areas the plants are growing on fractured shale with very little fine textured soil (14,15). Soil depth varies from negligible to greater than 55 cm (22 inches) (14,15). Soil pH ranges from 7.2 to 8.8 (14,15,23). Observations indicate that the plant is habitat specific and is not found on other soils. The clay hills on which the plants are often found form locally rolling topography, and often have a "badlands" appearance. Frequently they support sparser vegetation than adjacent areas of different substrate. Siler pincushion cactus is found on all aspects (14,15,23) on such hills, and is found on slopes varying from 0 to 80 percent (23). The known elevational range is from 850 to 1650 meters (2800 to 5400 feet) (14). The average annual precipitation is 25.8 cm (10 inches). Of this, 30 percent usually falls in July through September. Precipitation during this period is in the form of high intensity, short duration thunderstorms associated with strongly heated, moist air which advances into AZ from the southwest and the Gulf of Mexico. The average seasonal snowfall is 26 cm (10.6 inches). Winter snowfalls develop from frontal advances originating in the Pacific Northwest (26). The average frost-free season is 196 days (23). In winter the average temperature is 2 degrees C (35 degrees F) and the average daily minimum temperature is minus 7 degrees C (20 degrees F). In summer the average temperature is 24 degrees C (75 degrees F) and the average daily maximum is 32 degrees C (90 degrees F) (26). The off-road vehicle threat is most intense near populated areas such as St. George (28), Pipe Springs/Moccasin, and Fredonia, AZ (22). Trampling and habitat destruction by cattle is most severe in areas of concentrated use such as near water and salt sources, and corrals. There plants grow in shrub understory or along gully slopes where they are protected from trampling (16). P. sileri occurs in the shrub and brush rangeland land use/land cover associations, specifically in the sagebrush, desert shrub and pinyon-juniper forest/rangeland associations. The vegetation is of low stature (less than 1 meter tall) and very sparse. Pinyons and junipers are about 3 to 4 meters tall; the canopy is open (14,15,16). As a result of its rather large elevational range and its substantial east-west geographic distribution, there is considerable variation from site to site in plant species associated with Siler pincushion cactus. Dominant associated species include: Atriplex confertifolia (Shadscale), Atriplex canescens (four-wing saltbush), Artemisia tridentata (big sagebrush), Artemisia bigelovii (flat Habitat Associations - 1 sagebrush), Gutierrezia sarothrae (snakeweed), Salvia dorrii (desert sage), Eriogonum corymbosum (shrubby wild buckwheat), Eriogonum microthecum (slender buckwheat brush), Chrysothamnus nauseosus, Chrysothamnus viscidiflorus (rabbitbrush), Ephedra spp. (Mormon tea), Hilaria jamesii (Galleta), and Oryzopsis hymenoides (Indian rice- grass) (13,14,15,22,23,28). At higher elevation sites, associated species include: Pinus edulis (Colorado pinyon), Juniperus osteosperma (Utah juniper), Cowania mexicana (cliffrose), and Yucca baccata (Banana yucca). At some low elevation sites, it is associated with: Larrea divaricata ssp. tridentata (creosotebush), Ambrosia dumosa (white bursage), and other species of low elevation desert. At one site in Washington County, Utah, is found the dwarf bear-poppy (Arctomecon humilis), a listed Endangerd species, and at other sites near Fredonia, Arizona, it occurs with Eriogonum mortonianum and Eriogonum thompsonae var. atwoodii which at this time are candidate species for possible listing under the Endangered Species Act (13,14,15,22,23). Habitat Associations - 2
                                (DRAFT) - Food Habits
                          Species CACTUS, PINCUSHION, SILER
                                Species Id ESIS702018
                                   Date 13 MAR 96



FOOD HABITS

TROPHIC LEVEL - AUTOTROPH Food Habits - 1
                         (DRAFT) - Environment Associations
                          Species CACTUS, PINCUSHION, SILER
                                Species Id ESIS702018
                                   Date 13 MAR 96



ENVIRONMENTAL ASSOCIATIONS

G = General A = Adult LIM = Limiting RA = Resting Adult J = Juvenile FA = Feeding Adult RJ = Resting Juvenile BA = Breeding Adult FJ = Feeding Juvenile P = Pupae L = Larvae E = Egg RL = Resting Larvae FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS G G G G G Environment Associations - 1
                               (DRAFT) - Life History
                          Species CACTUS, PINCUSHION, SILER
                                Species Id ESIS702018
                                   Date 13 MAR 96



LIFE HISTORY

HABIT: Succulent (06,07). LIFE CYCLE: Perennial (06,07). TYPE OF REPRODUCTION: Sexual (23). REPRODUCTIVE PHENOLOGY: Pediocacti usually form buds in fall, but do not open until spring (08,17). However, Fletcher (12) did not observe buds on the species he located in April. Germination dates are unknown, anthesis occurs from April to early May, and fruiting dates are from May to June (08,12,17,23). Fruit dispersal occurs sometime before mid- September. SEX OR SPORE STATUS: Monoclinous (03,06,07,19,23). POLLINATION, SPORE AND SEED DISSEMINATION: Pollen dissemination agents are unknown, however the seed dissemination agents presumably are wind and rain water (17,22). Dispersal of the genus seems to be limited by the dry, dull- colored fruits which do not appear to attract birds or rodents. Apparently wind and rain water are responsible; this tends to produce relatively scattered colonies with fairly high density (17). Often these small populations are separated by distances of several miles even when suitable habitat is contiguous. Disturbance of the habitat by overgrazing or off-road vehicles causes erosion and compaction of soil, and influences success of seeds being dispersed to suitable habitats (14,16,23). SEED BIOLOGY: Amount of and variation in annual seed production, seed viability, longevity, and percent germination have not been studied. Pediocacti in general require summer dormancy (08,17), although Pediocactus sileri does not retract into the soil as other species do (17). The germination requirements described here are applicable to Pediocactus and Sclerocactus and apply to greenhouse conditions (08, 17). 1) First month: temperature minus 8 degrees C (20 degrees F) night, 2 to 5 degrees C (35 to 40 degrees F) day; soil 50 percent peat moss, 50 percent sand; mist and bottom water pot; not in full sun. 2) Two weeks: 5 to 20 degrees C (40 to 70 degrees F) night to day; moist. 3) 10 to 40 degrees C (50 to 110 degrees F), partial shade, wet and humid one week per month, drying out for 3 weeks. 4) Late fall let dry for 2 months. Life History - 1 (DRAFT) - Life History Species CACTUS, PINCUSHION, SILER Species Id ESIS702018 Date 13 MAR 96 Seedlings are removed when they germinate and put in partial sun, fresh air, given occasional waterings and feedings, and cooler temperatures rather than warm (08). Heil et al. (17) advocates stratification of seeds by freezing dry seeds 30 days at 1 degree C; and notes that the species is especially susceptible to root rot. POPULATION BIOLOGY: Limiting factors for Pediocactus sileri include: specialized soil type, cold winters, summer dormant period, and drying out periods (07, 08,17,22,23). This species appears to be in a healthy reproductive state (23). Although several dead plants occur at most sites, several size classes (including young plants) are represented in each population, and fruiting success appears high. Forty-seven fruits were attached to 36 plants in one population; 50 percent of the plants were flowering in another study (23). Populations vary greatly in size, number of individuals (frequently less than 12 individuals per population) (12), range 18 to 530 per population in another study (14), and density (12,13,14,15,16). Often populations are separated by distances of several miles even when suitable habitat is contiguous (17). Plants are eaten by rabbits, rodents, and insect larvae (14,16, 23), and trampled by cattle (16,23). Without the adverse impacts caused by man, Pediocactus sileri appears to have stable, viable populations, and therefore favorable recovery potential (22). ECOLOGICAL/EDAPHIC FACTORS: Pediocactus sileri is generally found on gypsiferous and calcareous clay soils mostly derived from various members of the Triassic Age Moenkopi Formation. It is sometimes found on nearly identical-appearing members of the Chinle and Kaibab Formations, above and below the Moenkopi, respectively (13,14,15,16,22,23). The soils apparently are high in soluble salts and are usually white, although they occasionally are red if derived from one of the red members of the Moenkopi Formation (14,15,23). Soil texture varies from very gravelly or shaley sandy loam through fine sandy loam to clay loam. In some areas the plants are growing on fractured shale with very little fine textured soil (14,15). Soil depth varies from negligible to greater than 55 cm (22 inches) (14,15). Soil pH ranges from 7.2 to 8.8 (14,15,23). Siler pincushion cactus is found on all aspects of slope (14,15, 23), varying from 0 to 80 percent (23). The known elevational range is from 850 to 1650 meters (2800 to 5400 feet) (14). The average annual precipitation is 25.8 cm (10 inches). The average seasonal snowfall is 26 cm (10.6 inches). The average frost- free season is 196 days (23). In winter the average temperature is 2 degrees C (35 degrees F) and the average daily minimum temperature is minus 7 degrees C (20 degrees F). In summer the average temperature is 24 degrees C (75 degrees F) and the average daily maximum is 32 degrees C (90 degrees F) (26). The plant normally grows in full sunlight. According to Jorgenson (32), Soil Survey Party Leader, SCS, St. George, the badland soils on which this cactus grows have not been surveyed, classified or mapped. Therefore it is not possible to state Life History - 2 (DRAFT) - Life History Species CACTUS, PINCUSHION, SILER Species Id ESIS702018 Date 13 MAR 96 soil order and series for this species. TROPHIC STATUS: The Siler pincushion cactus is phototrophic (29). Cacti have Crassulacean Acid Metabolism (CAM). Carbon dioxide is absorbed at night, incorporated first into malic or isocitric acid by a reversible process requiring darkness. At low temperatures the equilibrium lies toward the acid side, but at higher temperatures carbon dioxide is released. The lower the night temperatures the more carbon dioxide that can be fixed as an organic acid and the more that will be available the next day for photosynthesis. Therefore cacti do well where there is a pronounced periodicity in their environment, such as in arid regions (29). CHARACTERISTIC DOMINANCE: Component (12,13,14,15,16,23). Populations vary greatly in the numbers of individuals and ranged from 18 to 530 per population in one survey (16), with a range in density (plants per unit area) (12). Plants are usually widely scattered in each population (12,23), although in one high density area 72 plants were counted from one spot (14). COMMUNITY ECOLOGY: Siler pincushion cactus grows on the specialized Moenkopi outcrops discussed in the above sections concerning habitat and Ecological/Edaphic Factors. Most of the populations are in the Great Basin Desert Scrub Biotic Communities, while a few of the higher elevation sites are in the Great Basin Conifer Woodland and Plains and the Great Basin Grassland, and low elevation sites are in the Mohave Desert Scrub (10,14,23). The plants in these communities are generally low in stature (less than 1 meter tall, except for pinyon and juniper), and vegetative cover is sparse. No quantitative data is available. With the exception of possible influence of livestock grazing (16), these communities can be considered stable climax communities. Any modification of the habitat would probably have a negative impact on the species. SPECIES INTERRELATIONSHIPS: Siler pincushion cactus is used as a food source by rabbits and rodents (16,23). Insect larvae also eat the plants (14,16). Populations around Fredonia, AZ, were being heavily infested by insect larvae in 1985. Few live plants could be found at that time (33). OTHER LIFE HISTORY DESCRIPTORS: None. Life History - 3
                           (DRAFT) - Management Practices
                          Species CACTUS, PINCUSHION, SILER
                                Species Id ESIS702018
                                   Date 13 MAR 96



MANAGEMENT PRACTICES

RESULT MANAGEMENT PRACTICE Beneficial Controlling/Restricting Off-Road Vehicles Beneficial Restricting/regulating human disturbance of populations Beneficial Controlling/Restricting Mining Beneficial Stocking captive-reared wild-strain animals Beneficial Restricting Poaching Beneficial Controlling/Restricting Noncommercial Harvest Beneficial Regulating commercial harvest levels Beneficial Controlling/Removing Domestic Animals Adverse Collecting Existing Collecting Adverse Off Road Vehicles Existing Off Road Vehicles Adverse Existing Adverse Low Gene Pool Existing Low Gene Pool Adverse Disease Existing Disease Adverse Predation Existing Predation Adverse Surface Mines Existing Surface Mines Adverse Reservoirs Existing Reservoirs Adverse Erosion Existing Erosion Adverse Grazing Existing Grazing COMMENTS ON MANAGEMENT PRACTICES - At the time of listing as an Endangered species the perceived threats to P. sileri were (23,27): strip mining of gypsum deposits, off-road vehicle use (12), the Warner Valley Project in UT (28), collection (12,20,21,28), trampling and habitat destruction by cattle, and the restriction of the species to a specialized and localized soil type with low total population levels in small scattered disjunct populations (12,23). Intensive searches by BLM personnel from 1976 to 1979 significantly increased the numbers of known populations and individuals (13,14,15,16,30). Some of these populations are on substrate of low economic value and are in more remote localities (14, 16) so that some of the immediate threats of gypsum mining and collection is removed (22,30). The off-road vehicle threat is most intense near populated areas such as St. George (28), Pipe Springs/Moccasin, and Fredonia, AZ (22). Trampling and habitat destruction by cattle is most severe in areas of concentrated use such as near water and salt sources, and corrals. There plants grow in shrub understory or along gully slopes where they Management Practices - 1 (DRAFT) - Management Practices Species CACTUS, PINCUSHION, SILER Species Id ESIS702018 Date 13 MAR 96 are protected from trampling (16). Disturbance of the habitat by overgrazing or off-road vehicles causes erosion and compaction of soil, and influences success of seeds being dispersed to suitable habitats (14,16,23). At most sites the extent of contiguous habitat is small, both increasing the vulnerability of large populations to collection due to their density, and of small populations due to the potential of extirpation by removal of only a few plants (22). Erosion and loss of plants on steep slopes, and damage to roots, apical meristems, and fruits due to rabbits, rodents (i.e., predation), and insects (i.e., disease) has been noted (14,16,23). Limiting factors for Pediocactus sileri include: specialized soil type, cold winters, summer dormant period, and drying out periods (07, 08,17,22,23). Since the species was listed, an additional mining threat has surfaced on much of the Arizona Strip area. Much of the district has been claimed by uranium companies. This could possibly pose a future threat for the habitat of this species (22). APPROVED PLAN: U.S. Fish and Wildlife Service. 1986. Recovery Plan for the Siler Pincushion Cactus. U.S. Fish and Wildlife Service, Albuquerque, New Mexico. 57 pp. The major serious threats to Pediocactus sileri are habitat destruction (ORV use, mining and grazing) and collecting. Enforcement of existing regulations is the highest priority to prevent the extinction of this species. Planned actions include: 1) Preparation and implementation of a Habitat Management Plan for Pediocactus sileri on BLM lands. 2) Controlling ORV's (limiting human access) through existing BLM regulations. 3) Preparation of a Mineral Feasibility Report for BLM lands within Pediocactus sileri range that will evaluate the probability of minable deposits of gypsum, uranium and other recoverable minerals on public lands and then evaluate the risk involved for Pediocactus sileri. 4) Preparation of a grazing management plan for allotments which will involve Section 7 consultation and should contain; a) elimination of spring grazing, b) complete elimination of grazing from known high density cactus populations, and c) banning of the high intensity/short duration Savory grazing method. 5) Controlling collecting by enforcement of the Endangered Species Act, CITES, the Lacey Act and Arizona State Law. The Recovery Plan also recommends: 1) Studies on the ecology and population biology of Pediocactus sileri including; a) soil needs, b) water needs, Management Practices - 2 (DRAFT) - Management Practices Species CACTUS, PINCUSHION, SILER Species Id ESIS702018 Date 13 MAR 96 c) the effect of small herbivores, d) determining pollinators, e) life history requirements, and f) demographic trends, and the application of this information to land and species management plans. 2) Searches for other populations within the known area and in suitable habitat nearby. 3) Protection of known populations on private lands by enforcing existing laws. 4) Implementation of a Habitat Management Plan and designation of occupied and potential habitat as an Area of Critical Environmental Concern by the BLM. 5) Documentation of collecting losses through permanent plots. 6) Develop propagation techniques to provide nursery stocks both to reduce collecting and for possible reintroduction. 7) Develop public awareness, appreciation and support for the preservation of Siler pincushion cactus. Ongoing recovery activities include; development of a Habitat Management Plan, a Mineral Feasibility Report and a monitoring program. Management Practices - 3
                                   (DRAFT) - References
                            Species CACTUS, PINCUSHION, SILER
                                  Species Id ESIS702018
                                      Date 13 MAR 96



     

References

***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE ***** 01 Anonymous. 1931. Rare Utahia siler Engelmann. Cactus and Succulent J. (US) 3:88-89. 02 Backeberg, C. 1976. Cactus lexicon. 3rd ed. Blanford Press, Poole, Dorset, England. 03 Benson, L. 1961. A revision and amplification of Pediocactus I. Cactus and Succulent J. (US) 33:49-54. 04 Benson, L. 1962. A revision and amplification of Pediocactus II and III. Cactus and Succulent J. (US) 34:19; 57-60. 05 Benson, L. 1962. A revision and amplification of Pediocactus IV. Cactus and Succulent J. (US) 34:163-168. 06 Benson, L. 1969. The cacti of Arizona. 3rd ed. The Univ. of AZ Press, Tucson. 07 Benson, L. 1982. The cacti of of the United States and Canada. Stanford Univ. Press, Stanford, CA. 08 Brack, S. [n.d.]. Germination tips for Sclerocactus-Pediocactus- Toumeya. Unpubl. manu. 09 Britton, N.L. and J.N. Rose. 1922. The Cactaceae. Carnegie Inst. of Washington. Publ. No. 248; Vol. 3; p215. 10 Brown, D.E. and C.H. Lowe. 1977. Map, biotic communities of the Southwest. Rocky Mtn. Forest and Range Exp. Sta., USDA/FS. 11 Coulter, J.M. 1896. Preliminary revision of the North American species of Echinocactus, Cereus, and Opuntia. Contributions from the U.S. National Herbarium 3:355-462. 12 Fletcher, R. 1979. Status report, Pediocactus sileri. Unpublished report on file at: USDA/FS, Region 3. 13 Gierisch, R. 1979. Field reports on Pediocactus sileri. Submitted to AZ Strip District, BLM. 14 Gierisch, R. 1980. Pediocactus sileri (Engelm.) L. Benson in Arizona and Utah: observations and comments. Submitted to AZ Strip District, BLM. 15 Gierisch, R. 1981. Observations and comments on Pediocactus sileri in Arizona and Utah. Desert Plants 3:9-16. 16 Gierisch, R. 1980. A report on Pediocactus sileri (Engelm.) L. Benson in Arizona and Utah. Prepared for AZ Strip District, BLM. 17 Heil, K., B. Armstrong, and D. Schleser. A review of the genus Pediocactus. Cactus and Succulent J. (US) 53:17-39. 18 Kearney, T.H. and R.H. Peebles. 1960. Arizona flora, 2nd ed. with supplement by J.T. Howell, E. McClintock and collaborators. Univ. of CA Press, Berkeley. 19 Lindsay, G. 1941. Notes on Utahia sileri. Cactus and Succulent J. (US) 13:83-86. 20 Newland, K.C. 1979a. Statement presented at Fish and Wildlife Service hearings on the proposed Endangered cacti in Arizona, Phoenix, AZ. July 11, 1979. 21 Newland, K.C. 1979. [Letter to A.M. Phillips, III]. Evaluation of private and commercial collecting on five Arizona Endangered cactus species, July 1979. Located at the Mus. of Northern AZ, Flagstaff. 22 U.S. Fish and Wildlife Service. 1986. Recovery Plan for the Siler References - 1 (DRAFT) - References Species CACTUS, PINCUSHION, SILER Species Id ESIS702018 Date 13 MAR 96 Pincushion Cactus. U.S. Fish and Wildlife Service, Albuquerque, New Mexico. 57 pp. 23 Phillips, A.M., III, B.G. Phillips, L.T. Green, III, J. Mazzoni and E.M. Peterson. Status report: Pediocactus sileri (Engelm.) L. Benson. Prepared for the USFWS, Albuquerque, NM. 24 Schumann, K. 1902. Gesamtbeschreibung der Kakteen. P445. 25 Territories of New Mexico and Arizona. 1879. Map (scale 1: 1,500,000) prepared by the Office of the Chief of Engineers, USA. 26 USDA/SCS. Soil survey of Coconino County area, north Kaibab part. Draft manus. located in SCS Office, Phoenix, AZ. 27 U.S. Government. 1979. Determination that Pediocactus sileri is an endangered species. Federal Register 44:61786-61788. 28 Welsh, S.L. and K.H. Thorne. 1979. Illustrated manual of proposed Endangered and Threatened plants of Utah. USDI/FWS, BLM and USDA/ FS. 29 Went, F. 1982. The physiology of cacti. In: The cacti of the United States and Canada. Benson, L. Stanford Univ. Press, Stanford, CA. 30 Whitlock. 1980. (Memorandum to J.L. Spinks, Chief, OES, USFWS, Washington, DC). Subject: Determination that Pediocactus sileri is an Endangered species. 31 Wright, Y. 1932. Utahia sileri in flower. Cactus and Succulent J. (US) 4:213-214. 32 Jorgenson, W. June 3, 1985. Pers. comm. Soil Survey Party Leader, SCS, St. George, UT. 33 Brack, S. 1985. Pers. comm. ***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY ***** 01 Gierisch, R. 1981. Observations and comments on Pediocactus sileri in Arizona and Utah. Desert Plants 3:9-16. 02 U.S. Fish and Wildlife Service. 1986. Recovery Plan for the Siler Pincushion Cactus. U.S. Fish and Wildlife Service, Albuquerque, New Mexico. 57 pp. 03 U.S. Government. 1979. Determination that Pediocactus sileri is an endangered species. Federal Register 44:61786-61788. 04 Welsh, S.L. and K.H. Thorne. 1979. Illustrated manual of proposed Endangered and Threatened plants of Utah. USDI/FWS, BLM and USDA/ FS. References - 2