(DRAFT) - Taxonomy
Species CACTUS, TURK'S HEAD, NICHOL'S
Species Id ESIS702009
Date 13 MAR 96
TAXONOMY
NAME - CACTUS, TURK'S HEAD, NICHOL'S
OTHER COMMON NAMES - CACTUS, TURK'S HEAD, NICHOL'S; CACTUS, TURK'S HEAD, NICHOL;CACTUS, CLAW and EAGLE
ELEMENT CODE -
CATEGORY - Angiosperm
PHYLUM AND SUBPHYLUM - MAGNOLIOPHYTA,
CLASS AND SUBCLASS - MAGNOLIOPSIDA,
ORDER AND SUBORDER - CARYOPHYLLALES,
FAMILY AND SUBFAMILY - CACTACEAE,
GENUS AND SUBGENUS - ECHINOCACTUS,
SPECIES AND SSP - HORIZONTHALONIUS, VAR.
SCIENTIFIC NAME - ECHINOCACTUS HORIZONTHALONIUS VAR.
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Nichol's Turk's Head Cactus
Echinocactus horizonthalonius var. nicholii L. Benson
KINGDOM: Plant GROUP: Angiosperm
DIVISION: Magnoliophyta CLASS: Magnoliopsida
ORDER: Caryophyllales FAMILY: Cactaceae
Echinocactus horizonthalonius var. nicholii is a small, blue-
green barrel cactus, reaching a maximum height of 45 cm (18 in) and
diameter of 20 cm (8 in). There are commonly 8 ribs on the plant,
which usually spiral on the trunk of mature plants. Each areole
consists of three robust central spines, one black and curving
downward and two red or basally pale gray curving upward, and 5 radial
spines. The central spines are about 2.5 cm (1 in) long, the radials
1.9 cm (0.75 in). The flowers are about 5 to 7 cm (2 to 2.8 in) in
diameter and are bright rose-pink. The fruits are densely covered
with soft woolly white hairs. This cactus invariably has a single
stem, but often several seedlings grow around its base, giving the
appearance of small clumps (02,03,09).
Forrest Shreve collected the first specimen in Arizona from Pima
County in 1918. Although A.A. Nichol considered the Arizona plants
different from the Texas ones, the Arizona populations were only
Taxonomy - 1 (DRAFT) - Taxonomy
Species CACTUS, TURK'S HEAD, NICHOL'S
Species Id ESIS702009
Date 13 MAR 96
recently recognized as distinctive variety nicholii (02). The more
eastern populations are recognized as variety horizonthalonius.
Several varieties have been named under E. horizonthalonius,
including centrispinus, curvispinus, moelleri and obscurispinus, but
are not recognized now by most cactus specialists (09). Weniger (15)
used E.h. var. moelleri Haage Jr. to include from the El Paso, TX,
area west to Arizona. Benson (03) concluded that var. moelleri is a
nomen nudum because it lacked a Latin diagnosis, a type specimen, or a
previous page reference. Therefore, Benson included it under synonymy
of E.h. var. horizonthalonius. Synonyms for the common name include
eagle claw cactus and Nichol Turk's head cactus.
The type specimen is deposited at POM. The most complete and
accurate original descriptions are those of Lyman Benson (02,03).
Photographs of the taxon are in the same publications (02,03). A
drawing is on file at the U.S. Fish and Wildlife Service, Endangered
Species Office, Albuquerque, NM, and utilized on the Bureau of
Land Managements Habitat Management Plan (06). Another occurs in
Benson (03). Specimens have been deposited at herbaria at Desert
Botanical Garden, Pomona College, United States National Herbarium and
the University of Arizona.
Taxonomy - 2 (DRAFT) - Status
Species CACTUS, TURK'S HEAD, NICHOL'S
Species Id ESIS702009
Date 13 MAR 96
STATUS
Coded Status
E: Federal Endangered
Commercial
Non-consumptive recreational
Ornamental
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The Nichol's Turk's head cactus (Echinocactus horizonthalonius
var. nicholii) 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 State of Arizona.
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
action authorized, funded, or carried out by that agency is not likely
Status - 1 (DRAFT) - Status
Species CACTUS, TURK'S HEAD, NICHOL'S
Species Id ESIS702009
Date 13 MAR 96
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: 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 may be of value for some of
its yet undetermined phytochemical products and it has value as a
component of Arizona'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
79/10/26:44 FR 61927/61929 - 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
Strip Mines, Quarries, and Gravel Pits
COMMENTS ON HABITAT ASSOCIATIONS -
Nichol's Turk's head cactus is restricted to soils derived from
limestone (06,09). Observations indicate that the plant is habitat
specific and is not found on other soils. It occurs on the
Pennsylvanian-aged Harquilla Limestone, the Permain Earp Formation,
the Permian Concha Limestone and the Mississippian Escambrosa
Limestone (06,10,11). Elevations range from 750 to 1250 m (2460 to
4100 ft) (06).
Populations grow on the St. Thomas Soil Series (07). This is in
the Lithic Torriorthents Subgroup. Soils are loamy skeletal,
carbonatic and thermic. Soil texture is very gravelly or cobbly sandy
loam with greater than 40 percent calcium carbonate. Soil depth
varies from 10 to 51 cm (4 to 14 in) (20). The soils are in
Hydrologic Group D, which means that very little water is absorbed and
most runs off (07). Soil pH is 7.8 to 8.4 (07,12).
In one population area which has been studied extensively the
taxon grows in two distinctive habitat types; on dissected alluvial
fans at the mountain foot and on inclined terraces and saddles on the
mountain proper (09). Nichol's Turk's head cactus is found on all
aspects on such hills, and is found on slopes varying from 0 to 20
degrees (12). Soil erosion is an important factor; half-buried plants
do not grow well and rodents eat plants that have washed out or have
been injured (08).
There are differences in fecundity and survival curves for plants
in rocky terrace versus alluvial habitats (08,09). Populations are
denser at the higher sites where there is more moisture and more
rocks. Seedlings establish in soil pockets formed by emergent rocks.
In the alluvial habitat type, plants grow in the most open, exposed
areas containing few plants in the shrub-tree strata. Shaded plants
grow, flower and survive at lower rates than plants in the open (08,
09). In the open rockless areas of the alluvial habitat type,
survivorship of seedlings is influenced by the survivorship of the
adults because the safe sites for seedlings are right next to the
female parent. By the time the larger plant dies, at least one of the
"pups" can take its place (08).
The climate of this area is semi-arid, with precipitation 24 to
33 cm (9.6 to 13 in) annually (13). More than half of the total
moisture falls as summer thundershowers that enter Arizona from the
Gulf of Mexico between July and September. The remaining moisture is
received in midwinter when middle latitudes cyclones, originating in
the Pacific Ocean, occasionally move far enough south to affect
Arizona (13). July temperatures range from lows of 16 to 29 degrees C
(61 to 84 degrees F) to highs of 32 to 44 degrees C (90 to 111 degrees
F). January temperatures range from lows of -10 to 16 degrees C (14
to 61 degrees F) to highs of 7 to 31 degrees C (45 to 88 degrees F)
(13). The average frost-free period is 364 days (08).
Echinocactus horizonthalonius var. nicholii occurs in the Shrub
and Brush Rangeland land use/cover association, specifically in the
Paloverde-cactus shrub community of the Desert Shrub rangeland
association. Populations occur near or adjacent to quarries and
associated roads, an airstrip, and a mill site.
Habitat Associations - 1 Dominant associated species are: Foothill paloverde (Cercidium
microphyllum, triangleleaf bursage (Ambrosia deltoidea), white ratany
(Krameria grayi), brittlebush (Encelia farinosa), Opuntia phaeacantha,
saguaro (Carnegiea gigantea), ocotillo (Fouquieria splendens) and
buckhorn cholla (Opuntia acanthocarpa) (06). No quantitative data are
available on percentage ground cover, canopy closure or cover of
associated species.
Habitat Associations - 2 (DRAFT) - Food Habits
Species CACTUS, TURK'S HEAD, NICHOL'S
Species Id ESIS702009
Date 13 MAR 96
FOOD HABITS
TROPHIC LEVEL -
AUTOTROPH
Food Habits - 1 (DRAFT) - Environment Associations
Species CACTUS, TURK'S HEAD, NICHOL'S
Species Id ESIS702009
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
Environment Associations - 1 (DRAFT) - Life History
Species CACTUS, TURK'S HEAD, NICHOL'S
Species Id ESIS702009
Date 13 MAR 96
LIFE HISTORY
HABIT:
Succulent (02,03).
LIFE CYCLE:
Perennial (02,03).
TYPE OF REPRODUCTION:
Sexual (04,08,09,12).
REPRODUCTIVE PHENOLOGY:
Germination occurs in mid-summer (04), anthesis occurs in
late-April to mid-May and fruiting dates are May to June (04,07,12).
Flower number seems to depend on a combination of summer and winter
rain distribution (08).
SEX OR SPORE STATUS:
Monoclinous (01,02,03,08,12).
POLLINATION, SPORE AND SEED DISSEMINATION:
Pollen dissemination agents are bees, butterflies and ants (08).
Seed dissemination agents are birds and rain water (08). Seed
remaining in the apex of a dead plant may germinate years later (08).
Seeds move two meters downslope in rills in one week (08). Pollen
travels 80 m (240 ft) via pollinators within the population (08), and
the plants are outcrossers (08).
SEED BIOLOGY:
Fifty to 100 seeds are produced per fruit and 6 to 10 flowers
(1 to 5 fruits) occur per plant so there are an average of 200 seeds
produced per plant per year (04,12). There is a large variance
between number of seeds per fruit and the number of fruit (therefore
seeds) between individual plants (08). Flower number seems to depend
on a combination of summer and winter rain distribution (08).
Eighty percent of the seeds are viable after 1 to 2 years, and a
high percentage are still viabe after 20 years (04,08). A greater
percentage of the seed produced per year survives in the more rocky
mountain habitat type (08).
Germination occurs in mid-summer from old seed. Benson (02)
reported that the cactus does best in a shale soil or one that is made
up of 50 percent lime. Nichol's Turk's head cactus grows well in hot,
wet summers (and are fairly inactive in spring) so plants in
cultivation are fed and watered in the summer (04).
POPULATION BIOLOGY:
Limiting factors for Nichol's Turk's head cactus include size of
mountain range; limestone soils; freezing temperatures; open unshaded
habitat; and "safe sites" for seedling establishment (08,09).
Population dynamics are slow for this cactus, and the turnover
rate is low (08). The mean age is 9.5 to 13+ years and maximum age
varies from 24 to 39 years in the populations which have been studied.
Plants to 69 years are reported (08). These populations show
Life History - 1 (DRAFT) - Life History
Species CACTUS, TURK'S HEAD, NICHOL'S
Species Id ESIS702009
Date 13 MAR 96
multimodal distributions of ages and young plants range from 48 to 80
percent of the populations. Growth rates are uniform within local
populations but differ among populations (09). Densities range from
2.3 to 8.6 plants per 1000 square meters (12).
There are differences in fecundity and survival curves for plants
in rocky terrace versus alluvial habitats (08,09). Populations are
denser at the higher sites where there is more moisture and more
rocks. In the alluvial habitat type, plants grow in the most open,
exposed areas containing few plants in the shrub-tree strata. Shaded
plants grow, flower and survive at lower rates than plants in the
open (08,09). Soil erosion is an important factor; half-buried
plants do not grow well and rodents eat plants that have washed out or
been injured.
Without the adverse impacts caused by man, Echinocactus
horizonthalonius var. nicholii appears to have stable, viable
populations, and therefore favorable recovery potential (09).
ECOLOGICAL/EDAPHIC FACTORS:
Nichol's Turk's head cactus is restricted to soils derived from
limestone (06,09). Observations indicate that the plant is habitat
specific and is not found on other soils. It occurs on the
Pennsylvanian-aged Harquilla Limestone, the Permain Earp Formation,
the Permian Concha Limestone and the Mississippian Escambrosa
Limestone (06,10,11). Elevations range from 750 to 1250 m (2460 to
4100 ft) (06).
Populations grow on the St. Thomas Soil Series (07). This is in
the Lithic Torriorthents Subgroup. Soils are loamy skeletal,
carbonatic and thermic. Soil texture is very gravelly or cobbly sandy
loam with greater than 40 percent calcium carbonate. Soil depth
varies from 10 to 51 cm (4 to 14 in) (20). The soils are in
Hydrologic Group D, which means that very little water is absorbed and
most runs off (07). Soil pH is 7.8 to 8.4 (07,12).
In one population area which has been studied extensively the
taxon grows in two distinctive habitat types; on dissected alluvial
fans at the mountain foot and on inclined terraces and saddles on the
mountain proper (09). Nichol's Turk's head cactus is found on all
aspects on such hills, and is found on slopes varying from 0 to 20
degrees (12). Populations are denser at the higher sites where there
is more moisture and more rocks. Shaded plants grow, flower and
survive at lower rates than plants in the open (08,09).
The climate of this area is semi-arid, with precipitation 24 to
33 cm (9.6 to 13 in) annually (13). More than half of the total
moisture falls as summer thundershowers that enter Arizona from the
Gulf of Mexico between July and September. The remaining moisture is
received in midwinter when middle latitudes cyclones, originating in
the Pacific Ocean, occasionally move far enough south to affect
Arizona (13). July temperatures range from lows of 16 to 29 degrees C
(61 to 84 degrees F) to highs of 32 to 44 degrees C (90 to 111 degrees
F). January temperatures range from lows of -10 to 16 degrees C (14
to 61 degrees F) to highs of 7 to 31 degrees C (45 to 88 degrees F)
(13). The average frost-free period is 364 days (08).
TROPHIC STATUS:
Life History - 2 (DRAFT) - Life History
Species CACTUS, TURK'S HEAD, NICHOL'S
Species Id ESIS702009
Date 13 MAR 96
Phototrophic (16). 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 temperature 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 does well where there is a pronounced
periodicity in their environment, such as in arid regions (06).
CHARACTERISTIC DOMINANCE:
Component (06,08,09,12). Densities range from 2.3 to 8.6 plants
per 1000 square meters (12). There are differences in fecundity and
survival curves for plants in different habitats (08,09). Populations
are denser at the higher sites where there is more moisture and more
rocks. In the open, rockless areas of the alluvial habitat type
plants grow in the most open, exposed areas containing few plants in
the shrub-tree strata. Shaded plants grow, flower and survive at
lower rates than plants in the open (08,09).
COMMUNITY ECOLOGY:
Nichol's Turk's head cactus grows in the limestone habitats
discussed in "Ecological/Edaphic Factors." The populations are in
climax associations of the Arizona Upland Division of the Sonoran
Desertscrub (05). The vegetation consists of scattered small trees
and shrubs with considerable open ground between them. No
quantitative data are available on the associated plant communities
(08). Any modification of the habitat (such as blading, introduction
of grasses, increased grazing, etc.) would probably have a negative
impact on the species (08).
SPECIES INTERRELATIONSHIPS:
Packrats eat the plants after washout or injury (08). Birds eat
the seeds (08) and ants attack the nectaries (08).
OTHER LIFE HISTORY DESCRIPTORS:
None.
Life History - 3 (DRAFT) - Management Practices
Species CACTUS, TURK'S HEAD, NICHOL'S
Species Id ESIS702009
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 Restricting/regulating human use of habitats
Beneficial Land Acquisition
Beneficial Stocking captive-reared wild-strain animals
Beneficial Restricting Poaching
Beneficial Controlling/Restricting Noncommercial Harvest
Beneficial Regulating commercial harvest levels
Adverse Collecting
Existing Collecting
Adverse Off Road Vehicles
Existing Off Road Vehicles
Adverse Hiking/Camping
Existing Hiking/Camping
Adverse Surface Mines
Existing Surface Mines
Adverse Highway/Railroads
Existing Highway/Railroads
Adverse Soil compaction by heavy equipment in mine areas
Existing Soil compaction by heavy equipment in mine areas
COMMENTS ON MANAGEMENT PRACTICES -
At the time of listing as an Endangered species, percieved
threats to Echinocactus horizonthalonius var. nicholii were (12,14);
mining of limestone deposits, off-road vehicle use and collection.
Mining activity is a major threat to the existence of this taxon.
The mountain habitat contain a high grade lime of commercial value in
the sugar beet and cement industries. Quarrying of limestone has
already extirpated a small population growing on the Papago Indian
Reservation on patented lands. Roads leading to this quarry have cut
through several populations and erosion is burying and washing out
plants (06,09). Construction of an airstrip and mill site on BLM
administered land destroyed an estimated 350 plants (06).
Since 1974 motorcycles and all-terrain vehicles have killed
considerable numbers of plants (06,08,09). Off-road vehicle threat is
most intense near roads constructed by the mines but ORV use is not
restricted to established roads. Camping by winter visitors along the
Papago Indian Reservation boundary was a yearly event until the Papago
Indians discouraged this practice. Parking vehicles and establishing
camp sites in the level, open spaces destroyed a large fraction of the
population in this area.
Although Benson (01) stated that plants were fast disappearing,
cactus collectors did not appear to be a serious problem at this time
(09). Seed collection by commercial cactus nurseries may be a serious
problem, because collecting methods can damage the central meristem of
this cactus and prevent further growth and flowering (06,08,09). At
least one nursery collects seed in this area and there are plants
Management Practices - 1 (DRAFT) - Management Practices
Species CACTUS, TURK'S HEAD, NICHOL'S
Species Id ESIS702009
Date 13 MAR 96
which appear to have been damaged permanently by this practice (08).
BLM recently approved a mining plan to operate a crushing and
screening facility on a previously bladed mill site. The copious
amounts of dust created may coat the plants and harden, allowing
little moisture to reach the plants, thus reducing the plants'
photosynthetic rate. This impact might not be noticed for many years
(06). Development of deposits of copper, silver, gold and cobalt
occurring in the mountains would destroy plants (06).
APPROVED PLAN:
U.S. Fish and Wildlife Service. 1986. Nichol Turk's Head Cactus
(Echinocactus horizonthalonius var. nicholii) Recovery Plan. U.S.
Fish and Wildlife Service, Albuquerque, New Mexico. 69 pp.
The major serious threats to Nichol's Turk's head cactus are
habitat destruction (particularly ORV use and mining) and collection.
Enforcing compliance with Section 7 of the Endangered Species Act and
Section 38009,2-2d of the Surface Management of Public Lands
regulations will decrease impacts of active limestone mines within the
Nichol's Turk's head cactus range. Management of populations of
Nichol's Turk's head cactus on Federal lands should include:
1) Withdrawal of unclaimed suitable habitat on BLM lands from
operation of mining laws.
2) Adding invalid, inactive claims to withdrawals.
3) Consolidating Federal ownership.
4) Monitoring of a marked population near an active mine on BLM
land.
5) Development of ORV designation of appropriate portions of
habitat in the Waterman Mountains.
6) Cooperative efforts with BIA to survey, monitor and manage
Nichol's Turk's head cactus populations on the Papago
Reservation.
Protection of known populations on State and private lands by
enforcing existing laws, and management through cooperative agreements
is planned. Collection can be limited by enforcing the Endangered
Species Act, CITES, Lacey Act and the Arizona Native Plant Law. The
Recovery Plan also recommends:
1) Studies on the ecology and population biology of Nichol's
Turk's head cactus including;
a) soil needs,
b) water needs,
c) effects of small herbivores,
d) determining pollinators,
e) life history requirements,
f) demographic trends and the application of this
information to management plans.
2) Searches for other populations within the known area in
Arizona, in nearby suitable habitats and in the recently
discovered range in Sonora, Mexico.
3) Implementation of a Habitat Management Plan and designation of
an Area of Critical Environmental Concern.
Management Practices - 2 (DRAFT) - Management Practices
Species CACTUS, TURK'S HEAD, NICHOL'S
Species Id ESIS702009
Date 13 MAR 96
4) Development of propagation techniques to provide nursery
stocks both to reduce collecting and for possible
reintroduction.
5) Develop public awareness, appreciation and support for the
preservation of Nichol's Turk's head cactus.
Current recovery efforts by the BLM have included drafting of a
Habitat Management Plan and the establishment of a monitoring plot in
the Waterman Mountains.
Management Practices - 3 (DRAFT) - References
Species CACTUS, TURK'S HEAD, NICHOL'S
Species Id ESIS702009
Date 13 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Benson, L. 1950. The cacti of Arizona, 2nd ed. The Univ. of AZ
Press, Tuscon.
02 Benson, L. 1969. The cacti of Arizona, 3rd ed. The Univ. of AZ
Press, Tuscon.
03 Benson, L. 1982. The cacti of of the United States and Canada.
Stanford Univ. Press, Stanford.
04 Brack, S. 1985. Pers. comm. Museum of Northern Arizona, Mesa
Garden, Box 72, Belen, NM 87002.
05 Brown, D.E., C.H. Lowe and C.P. Pase. 1980. A digitized
systematic classification for ecosystems with an illustrated
summary of the natural vegetation of North America. USDA/FS Gen.
Tech. Rept. No. RM-73. Rocky Mtn. For. and Rang. Exp. Sta., Fort
Collins, Co.
06 Butterwick, M. 1985. Nichol's Turk's head cactus habitat
management plan. Phoenix District, BLM. Manus.
07 Cochran, C. 1985. Pers. comm. Museum of Northern Arizona, USDA/
SCS, Tucson Office, 3241 Romero Road, Tucson, AZ 85705.
08 May, C.J. 1985. Pers. comm. Museum of Northern Arizona, Pima
Community College, Tucson, AZ.
09 U.S. Fish and Wildlife Service. 1986. Nichol Turk's Head Cactus
(Echinocactus horizonthalonius var. nicholii) Recovery Plan. U.S.
Fish and Wildlife Service, Albuquerque, New Mexico. 69 pp.
10 McClymonds, N.E. 1957. Stratigraphy and structure of the
Waterman Mountains, Pima County, AZ. MS Thesis, Univ. of AZ,
Tucson.
11 McClymonds, N.E. 1959. Paleozoic stratigraphy of the Waterman
Mountains, Pima County, AZ. L.A. Heindl (ed). AZ Geological Soc.,
Southern Arizona. Guidebook II.
12 Phillips, A.M., III, B.G. Phillips, L.T. Green, III, J. Mazzoni and
E.M. Peterson. 1979. Status report: Echinocactus horizonthalonius
Lemaire var. nicholii L. Benson. On file at: USFWS, Albuquerque,
NM.
13 Sellers, W.D. and R.H. Hill, eds. 1974. Arizona climate. The
Univ. AZ Press, Tucson.
14 U.S. Government. 1979. Determination that Echinocactus
horizonthalonius var. nicholii is an Endangered species. Federal
Register 44:61927-61929.
15 Weniger, D. 1970. Cacti of the Southwest. The Univ. of TX Press,
Austin.
16 Went, F. 1982. The physiology of cacti. In: The cacti of the
United States and Canada. Benson, L. Stanford Univ. Press,
Stanford.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 Butterwick, M. 1985. Nichol's Turk's head cactus habitat
management plan. Phoenix District, BLM. Manus.
02 Hunt, C.B. 1974. Natural regions of the U.S. and Canada. W.H.
References - 1 (DRAFT) - References
Species CACTUS, TURK'S HEAD, NICHOL'S
Species Id ESIS702009
Date 13 MAR 96
Freeman and Co., San Francisco.
03 U.S. Fish and Wildlife Service. 1986. Nichol Turk's Head Cactus
(Echinocactus horizonthalonius var. nicholii) Recovery Plan. U.S.
Fish and Wildlife Service, Albuquerque, New Mexico. 69 pp.
04 Phillips, A.M., III, B.G. Phillips, L.T. Green, III, J. Mazzoni and
E.M. Peterson. 1979. Status report: Echinocactus
horizonthalonius Lemaire var. nicholii L. Benson. On file at:
USFWS, Albuquerque, NM.
05 USDI/FWS. 1979. Determination that Echinocactus horizonthalonius
var. nicholii is an Endangered species. Federal Register 44:61927-
61929.
References - 2