CPC National Collection Plant Profile

Agave arizonica

Photographer:
Lynda Pritchett-Kozak

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CPC National Collection Plant Profile

Agave arizonica


Family: 
Agavaceae  
Common Name: 
Arizona agave
Author: 
Gentry & J.H. Weber
Growth Habit: 
Forb/herb, Shrub, Subshrub
CPC Number: 
44

Distribution
Protection
Conservation
References


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Agave arizonicaenlarge
Photographer: Lynda Pritchett-Kozak


Agave arizonica is Fully Sponsored
Primary custodian for this plant in the CPC National Collection of Endangered Plants is: 
Kathleen C. Rice contributed to this Plant Profile.

 
Agave arizonica


Agave arizonica was first discovered in 1959 in the New River Mountains of Arizona (Gentry 1970, 1982). It has been described as one of the rarest and most beautiful agaves in Arizona. The Arizona agave is a member of a prestigious family of plants, the Agavaceae. Within this family are numerous century plants that have been cultivated by humans for food, fiber, and alcohol uses.

The Arizona agave is considered to be a hybrid, reportedly from a cross between Agave chrysantha and A. toumeyana v. bella. This means that A. arizonica may be just starting down the path of evolution. (Nabhan 1989, Hodgson & DeLameter 1988, DeLameter & Hodgson 1987a, 1987b).

Agave arizonica is native to a small area in central Arizona, occurring on open rocky slopes in chaparral or juniper grassland at elevations from 1100 to 2750 m (3600-5800 ft). The distinctive bright green leaves of this species have mahogany margins and are generally arranged as single rosettes. This is a small plant, with a rosette of leaves reaching only ca. 30cm tall and 40cm broad at maturity. (Gentry 1982) Rosettes produce offsets sparingly in their native habitats, but when grown in cultivation plants produce clones prolifically in this manner. In May or June, a lucky observer may catch a glimpse the small, yellow jar-shaped flowers of this species that grace the top of 3-4 m long, slender stalk rising from the leaf rosette. Unfortunately, cattle grazing in areas where this species naturally occurs has severely impacted the ability of the Arizona agave to successfully produce flowers. In 1988, only 12 of 41 mature plants were able to produce flowers due to trampling and grazing from cattle in the area. (Hodgson & DeLameter 1988)

Because plants are of hybrid origin, seeds produced are not necessarily representative of the typical taxon.

Plants are reportedly of hybrid origin, with A. chrysantha, a relatively large agave, and A. toumeyana v. bella, a diminutive plant, as the parent species. Only 50-60 clones or plants have been located from distinct locations in Arizona where populations of the two putative parent species overlap.

The Desert Botanical Garden has a long history of study associated with A. arizonica, the majority of which has been conducted by W. Hodgson, Herbarium Curator and research botanist, in association with R. Delamater. All of the in situ controlled crosses, and subsequent seed collection was completed by Hodgson and Delamater.

Distribution & Occurrence

State Range
  Arizona
State Range of  Agave arizonica
Habitat
  Endemic to a very small area on steep, rocky granite slopes, or on level hilltops, sometimes close to drainages, at about 3,000 ft elevation in upper Sonoran Desert habitat (Ecker 1990, Hodges 1990). The surrounding vegetation is a chaparral association that is a transition from an oak-juniper woodland to a mountain mahogany-oak scrub community. (USFWS 1984, Brown 1994). Associated vegetation includes Agave chrysantha, A. toumeyana v. bella, Quercus turbinella, Dasyliron wheeleri, and Arctostaphyllos pungens (USFWS 1984, Ecker and Hodgson 1991).

Distribution
  The two populations are documented on the Tonto National Forest in central Arizona. One is located on steep granitic slopes in the New River Mountains (Maricopa and yavapai Counties). The other is located on relatively gentle hilltops and drainages in the Sierra Ancha Mountains (Gila County) (Fenner 1990, Anderson and Fenner 1990, Day and Fenner 1990, Anderson and Fenner 1992).

Number Left
  The Arizona agave has both a limited distribution and low numbers. In 1984, when the species was listed under the Endangered Species Act, 13 populations with 1 to 7 individual plants each were known, totaling less than one hundred individual plants for the entire species. (USFWS 1984)

Protection

Global Rank:  
G1Q
 
1/1/1996
Guide to Global Ranks
Federal Status:  
DO
 
6/19/2006
Guide to Federal Status
Recovery Plan:  
No
 

State/Area Protection
  State/Area Rank Status Date  
  Arizona S1 8/1/2002  

Conservation, Ecology & Research

Ecological Relationships
  The Arizona agave flowers in late May through June. A study conducted in 1988 (Hodgson & DeLameter) determined that bumblebees were the most frequent visitors to the inflorescences of this plant, as well as Halictidae bees, and even a wasp (Polistes sp.). Seed set appears moderate compared to A. chrysantha and A. toumeyana ssp. bella. Seed is gradually released via wind throughout the fall and winter.

Threats
  Illegal collection is a threat to this species, especially given its slow growth rate and extremely low population numbers. (Hurd and Albee 1976, USFWS 1984). Luckily, this plant grows in locations that are relatively isolated and difficult to reach.

Other threats include cattle and deer, which have been documented grazing on the sugar-rich inflorescences of Agave arizonica.

Current Research Summary
  Controlled crossed have been conducted on ex situ plants and those in habitat to ascertain whether or not A. chrysantha and A. toumeyana v. bella are indeed the true parents. Seeds resulting from these crosses produced 'typical' A. arizonica plants. Back-crosses from A. arizonica to one of the parents produced plants with characters varying in range between the two parent species, characteristic signs of introgression.

The Desert Botanical Garden has successfully grown this plant both from seed and tissue culture (Powers and Backhaus 1989).

Current Management Summary
  Tonto National Forest supported a trial augmentation conducted by the Desert Botanical Garden in the New River region (Kvale et al. 1989). Two plots containing ten plants each were watered several times, and then checked annually for establishment. After three years, only one or two plants remained. Suggested changes made to the experimental design for future attempts include alterations in site selection specifications, and in pre-conditioning of plants to be used.

The road into the main habitat where Agave arizonica occurs has been closed to limit access to this endangered species. (USFWS 1984)

An Allotment Management Plan (a document that applies to livestock operations on public lands or on lands within National Forests in the eleven contiguous western states--tailored to the specific range condition of the area where cattle are to be grazed, with the intent to improve the range condition of the lands involved) was signed in 1989 for the New River Allotment. This plan requires water developments for cattle to be placed greater than one-half mile from Agave arizonica, and that fences are erected one-quarter mile from known Agave arizonica locations during flowering periods. (Arizona Game and Fish Department 1997)

Research Management Needs
  Molecular work to determine variation within populations would be helpful in predicting the future status for this species.
Plants are long-lived (ca. 15-20 years), so at this point trends and demographic changes over the long term are unknown, but need to be determined in order for proper management of the species to occur.

Ex Situ Needs
  Controlled crosses between the parent species should be conducted to produce seeds for banking at Desert Botanical Garden and the National Seed Storage Laboratory in Ft. Collins, CO.

References

Books (Single Authors)

Brown, D.E. 1994. Biotic Communities/Southwestern United States and Northwestern Mexico. Salt Lake City, UT: University of Utah Press. 342p.

Gentry, H.S. 1982. Agaves of continental North America. Tucson, AZ: Univ. Arizona Press.

Kartesz, J.T. 1996. Species distribution data at state and province level for vascular plant taxa of the United States, Canada, and Greenland (accepted records), from unpublished data files at the North Carolina Botanical Garden.

Lehr, J.H. 1978. A Catalog of the Flora of Arizona. Phoenix, Arizona: Desert Botanical Garden. 33p.

Phillips, S.J.; Comus, P.W. 2000. A Natural History of the Sonoran Desert. Tucson, AZ: Arizona-Sonoran Desert Museum Press.

Books (Sections)

DeLamater, R.; Hodgson, W.C. 1987. Agave arizonica: An endangered species, a hybrid, or does it matter?. In: Elias, T.S., editor. Conservation and Management of Rare and Endangered Plants. California Native Plant Society. Sacramento, CA. p 305-309.

Kartesz, J.T. 1999. A synonymized checklist of the vascular flora of the U.S., Canada, and Greenland. In: Kartesz, J.T.; Meacham, C.A., editors. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden. Chapel Hill, NC.

Conference Proceedings

Pinkava, D.J.; Baker, M.A. Choromsome and Hybridization Studies of Agaves. Agave Symposium; Phoenix, Arizona. 1985.

Electronic Sources

(2000). Center for Plant Conservation's National Living Collection--Profiles. Desert Botanical Garden. http://www.dbg.org/Collections/cpc.html. Accessed: 2002.

Arizona Game and Fish Department. (1999). Plant Abstracts. Compiled and edited by the Heritage Data Management System, Arizona Game and Fish Department, Phoenix, AZ. http://www.gf.state.az.us/frames/fishwild/hdms_site/Abstracts/Plants/abstracts%20-%20plants.htm. Accessed: 2002.

ESIS. (1998). Endangered Species System (ESIS): Fish and Wildlife Exchange. [Web site;] Virginia Tech. http://fwie.fw.vt.edu/WWW/esis/. Accessed: 2002.

USFWS. (2002). U.S. Plant Profiles. U.S. Fish and Wildlife Service, International Affairs. http://international.fws.gov/animals/plantpro.html. Accessed: 2002.

Journal Articles

Burgess, T.L. 1985. Agave adaptation to aridity. Desert Plants. 7, 2: 39-50.

DeLamater, R.; Hodgson, W.C. 1987. Agave arizonica: A perplexing problem. Bulletin Board, Center for Plant Conservation. 2, 1: 9-10.

Falk, D.; Thibodeau, F.R. 1986. Saving the Rarest. Arnoldia. 46, 3: 2-17.

Gentry, H.S. 1970. Two new agaves in Arizona. Cactus and Succulent Journal of the Cactus and Succulent Society of America. 42: 223-228.

Limerick, S.; Olwell, M. 1984. Final Rule to Determine Agave arizonica (Arizona agave) to be an Endangered Species. Federal Register. 49, 98: 21055-21058.

Nabhan, G. 1989. Rescuing Arizona's Endangered Plants. Arizona Highways. 65: 35-41.

Powers, D.E.; Backhaus, R.A. 1989. In vitro Propagation of Agave arizonica Gentry and Weber. Plant Cell Tissue and Organ Culture. 16, 1: 57-60.

Reichenbacker, F.W. 1985. Conservation of Southwestern Agaves. Desert Plants. 7, 20: 103-107.

Schaffer, W.M.; Schaffer, M.V. 1977. The reproductive biology of Agavaceae: I. Pollen and nectar production in four Arizona agaves. Southwest Naturalist. 22: 157-168.

Schaffer, W.M.; Schaffer, M.V. 1979. The Adaptive Significance of Variations in Reproductive Habit in the Agavaceae II: Pollinator Foraging Behavior and Selection for Increased Reproductive Expenditure. Ecology. 60, 5: 1051-1069.

USFWS. 1975. Review of the Status of Vascular Plants and Determination of "Critical Habitat". Notice of Review. Federal Register. 40, 127: 27828.

USFWS. 1976. Proposed Endangered Status for 1700 U.S. Plants. Federal Register. 41: 24523-24572.

USFWS. 1976. Proposed Endangered Status for some 1700 US Vascular Plant Taxa--Proposed Rule. Federal Register. 40, 127: 24551.

USFWS. 1980. Review of Plant Taxa Proposed for Listing as Endangered or Threatened Species. Federal Register. 45, 242: 85206.

USFWS. 1983. Proposal to determine A. arizonica to be an endangered species. Federal Register. 48, 99: 22757-22760.

USFWS. 1984. Determination of Agave arizonica (Arizona agave) to be an Endangered Species. Federal Register. 49, 98: 21055- 21058.

USFWS. 1987. Notice of findings on petitions and initiation of status review. Federal Register. 52, 126: 24485-24488.

Reports

1997. Agave arizonica: Unpublished abstract. Phoenix, AZ: Compiled and edited by the Heritage Data Management System Arizona Game and Fish Department. p.4.

2002. General Species Information. Phoenix, Arizona: Arizona Ecological Services Field Office.

Anderson, L.; Fenner, P. 1992. Agave arizonica study 1992. Six BarAllotment, USFS, Tonto National Forest, Cave Creek Ranger District.

Day, B.; Fenner, P. 1990. Agave arizonica study on Bronco, Six-Bar and Ike's Backbone Allotments. USFS, Tonto National Forest, Cave Creek Ranger District.

Ecker, L.S. 1990. An Endangered Plant Species Profile: Agave arizonica. Phoenix, Arizona: USDA Forest Service, Tonto National Forest.

Ecker, L.S.; Hodgson, W.C. 1991. Investigation of Ecological, Horticultural, and Reproductive Requirements of Agave arizonica. Phoenix, Arizona: Desert Botanical Garden report for USDA Forest Service, Tonto National Forest.

Fenner, P. 1990. 1989 Agave arizonica surveys of Bronco, Six Bar and Ike's Backbone Allottments, Cave Creek Ranger District, Tonto National Forest. Phoenix, Arizona: Tonto National Forest.

Fletcher, J.R. 1978. USFS Status Report. Albuquerque, New Mexico: US Forest Service, Region 3.

Hodgson, W.; DeLamater, R. 1988. Agave arizonica Gentry & Weber: Summary of Status and Report on Recent Studies. Phoenix, AZ: Desert Botanical Garden. p.11.

Hodgson, W.C. 1990. First Annual Report for 1988. Phoenix, Arizona: Cooperative agreement between Desert Botanical Garden and USDA Forest Service, Tonto National Forest.

Hodgson, W.H.; DeLamater, R. 1989. Agave parviflora Torrey: Its distribution and status in Northern Mexico. U.S. Fish and Wildlife Service.

Hurd, ?.; Albee, L. 1976. Report on Agave arizonica. submitted to the USFS.

Kvale, R.; Boice, G.; Fenner, P.; Rhea, D. 1989. New River allottment management plan. Tonto National Forest, Cave Creek Ranger District.

Phillips, B.G.; Phillips, A.M., III; Mazzoni, J.; Peterson, E.M. 1980. Status Report: Agave arizonica Gentry and Weber. Albuquerque, New Mexico: Submitted USDI, US Fish and Wildlife Service. p.12.

Reichenbacher, F.W. 1986. Status report for Agave parviflora. Albuquerque, New Mexico: Prepared for USFWS.

Theses

Farringer, Eric Lee. 1989. A Photoacoustic Study of the Cuticular and Epidermal Layers of Leaves. [Ph.D. Thesis]: Arizona State University. 120p.


  This profile was updated on 3/4/2010
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