Saguaro Cactus Fact Sheet Plant Fact Sheet: Saguaro Cactus Identifying Features The saguaro cactus (Carnegiea gigantea) is one of the defining plants of the Sonoran Desert. These plants are large, tree-like columnar cacti that develop branches (or arms) as they age, although some never grow arms. These arms generally bend upward and can number over 25. Saguaros are covered with protective spines, white flowers in the late spring, and red fruit in summer. Habitat Saguaros are found exclusively in the Sonoran Desert. The most important factors for growth are water and temperature. If the elevation is too high, the cold weather and frost can kill the saguaro. Although the the Sonoran Desert experiences both winter and summer rains, it is thought that the Saguaro obtains most of its moisture during the summer rainy season. Range You find this cactus in southern Arizona and western Sonora, Mexico. At the northern portion of their range they are more plentiful on the warmer south facing slopes. A few stray plants can also be found in southeast California. Wild Status The saguaro is not currently listed as threatened or endangered.

Arizona has strict regulations about the harvesting, collection or destruction of this species. Life Span With the right growing conditions, it is estimated that saguaros can live to be as much as 150-200 years old. Size Saguaro are very slow growing cactus. A 10 year old plant might only be 1.5 inches tall. Saguaro can grow to be between 40-60 feet tall (12-18m). When rain is plentiful and the saguaro is fully hydrated it can weigh between 3200-4800 pounds. Quick Facts The saguaro is the largest cactus in the United States. Most of the saguaros roots are only 4-6 inches deep and radiate out as far from the plant as it is tall. There is one deep root, or tap root that extends down into the ground more than 2 feet. After the saguaro dies its woody ribs can be used to build roofs, fences, and parts of furniture. The holes that birds nested in or "saguaro boots" can be found among the dead saguaros.

Native Americans used these as water containers long before the canteen was available. Comparison Compare with the Desert Bloodwood Tree of the Australian Desert. Carnegiea gigantea Carnegiea gigantea REFERENCES INTRODUCTORY AUTHORSHIP AND CITATION : Pavek, Diane S. 1993. Carnegiea gigantea. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: [ ]. ABBREVIATION : CARGIG SYNONYMS : Cerceus giganteus Engelm. SCS PLANT CODE : CEGI COMMON NAMES : saguaro sahuaro giant cactus pitahaya TAXONOMY : The currently accepted scientific name for saguaro is Carnegiea gigantea (Engelm.) Britt. & Rose [ 32 ]. It is a member of the cactus family (Cactaceae). Carnegiea is a monotypic genus. There are no subspecies, varieties, or forms.

LIFE FORM : Cactus FEDERAL LEGAL STATUS : No special status OTHER STATUS : NO-ENTRY DISTRIBUTION AND OCCURRENCE SPECIES: Carnegiea gigantea GENERAL DISTRIBUTION : Saguaro occurs throughout most of the Sonoran Desert in Arizona, California, and Mexico [ 65 , 68 ]. The northern limits of its distribution are on the edge of the Hualapait Mountains in Arizona and along the Colorado River in southeastern California [ 30 , 32 , 40 , 65 ]. The range of saguaro extends southward; the largest populations of this species occur in Sonora, Mexico [ 67 ].

ECOSYSTEMS : FRES30 Desert shrub STATES : AZ CA MEXICO BLM PHYSIOGRAPHIC REGIONS : 7 Lower Basin and Range KUCHLER PLANT ASSOCIATIONS : K027 Mesquite bosque K041 Creosotebush K042 Creosotebush - bursage K043 Paloverde - cactus shrub K044 Creosotebush - tarbush SAF COVER TYPES : 241 Western live oak 242 Mesquite SRM (RANGELAND) COVER TYPES : NO-ENTRY HABITAT TYPES AND PLANT COMMUNITIES : Saguaro is a dominant or codominant member of the paloverde (Cercidium spp.)/saguaro (also known as the spinose suffrutescent community) and the paloverde/bursage (Ambrosia spp.) desertscrub community types on bajadas (i.e., eroded outwash fans) [ 35 , 46 , 74 , 75 , 78 ].

Infrequently, on the southwestern edge of its range, saguaro occurs in creosotebush (Larrea spp.) communities as a xeroriparian species in arroyos and washes [ 3 , 5 , 11 , 46 ]. Saguaro is a community type indicator species in the following publication: Vegetation of the Santa Catalina Mountains: Community types and dynamics [ 46 ]. MANAGEMENT CONSIDERATIONS SPECIES: Carnegiea gigantea IMPORTANCE TO LIVESTOCK AND WILDLIFE : The flowers, fruits, and seeds of the saguaro are important food sources for wildlife, such as collared peccary, long-nosed bats, heteromyid rodents, western white-winged doves, woodpeckers, and insects [ 2 , 19 , 39 , 50 , 56 ]. Saguaro fruits comprised a small amount (e.g., 1 to 5 percent of collected rumen contents) of mule deer summer diets [ 38 , 60 , 63 , 79 , 80 ].

The fruits were also utilized by desert bighorn sheep; they were present in 10 percent of bighorn fecal pellets analyzed [ 44 , 83 ]. Saguaro provides nesting habitat for birds and small mammals [ 49 ]. Saguaro mortality can have a high negative impact on bird species that use it for cover and nesting [ 9 ]. PALATABILITY : Saguaro is highly palatable to rodents and jackrabbits; however, saguaro tissue contains oxalates that deter some herbivory [ 47 , 68 ]. NUTRITIONAL VALUE : The nutritional value of saguaro fruits is variable throughout the season and among studies. Saguaro fruits are moderately digestible [ 80 ]. The amount of protein reported varied from 10 to 26 percent [ 33 , 80 ]. Acid detergent fiber amounts in the fruits varied from 26 to 62 percent, and dry matter was 11 to 35 percent [ 33 , 80 ]. COVER VALUE : Saguaro is considered a softwood snag [ 12 ].

Cavity-nesting birds, especially woodpeckers, and sometimes woodrats nest in saguaro [ 12 , 31 , 43 , 49 , 50 ]. VALUE FOR REHABILITATION OF DISTURBED SITES : NO-ENTRY OTHER USES AND VALUES : Saguaro fruits were a major food staple of the Papago and Pima Indians; the fruits were processed (i.e., dried, fermented, canned) and stored for year-round use [ 18 , 21 , 32 ]. Seeds, rich in fat, were ground for use as flour and in porridges [ 55 ]. Fruits were used for trade and in religious practices by the Papago Indians [ 21 , 57 ]. The internal heavy, woody ribs were used for firewood and building houses and fences [ 1 , 6 , 10 ]. Saguaro is grown in desert gardens as an ornamental [ 89 ]. It is the state flower of Arizona and is used in commercial advertisements of Southwestern living [ 40 ]. OTHER MANAGEMENT CONSIDERATIONS : Intensive grazing can prevent recruitment of saguaro seedlings [ 47 ].

Various areas in the Sonoran Desert have been protected from domestic livestock grazing for 50 years or more. One early study showed that there was no significant (p>0.05) difference between saguaro abundance on protected and unprotected plots [ 8 ]. More recent studies, however, have shown that saguaro increased by 33 to 200 percent in protected areas [ 27 , 77 ]. Saguaro seedlings may be impacted negatively when nurse plants are browsed [ 47 ]. Models to predict saguaro age from growth parameters (for example, height-age equivalents) have been developed [ 28 , 69 ]. In transplant experiments, mortality was 100 percent for unshaded saguaro seedlings compared to 65 percent for shaded seedlings [ 22 ]. Saguaro are susceptible to few diseases [ 10 ]. Healthy saguaro often wall off larvae tunnels, woodpecker holes, or other wounds [ 47 ]. Some necroses may occur, however, after mechanical damage to saguaro from breakage, frost, or lightning [ 71 ].

Insects, saprophytic yeasts, molds, and bacteria readily inhabit and breed in saguaro necroses [ 24 , 66 , 72 ]. Temperatures below 23 degrees Fahrenheit (-5 deg C) will damage saguaro. Death will occur after exposure to below freezing temperatures for 29 or more consecutive hours [ 85 ]. Fluctuations in saguaro numbers often are due to recurring catastrophic freezes [ 37 , 46 , 69 ]. Saguaro is protected under the Arizona Native Plant Law. Cactus poaching is of concern around Saguaro National Monument and urban centers [ 90 ]. Natural environmental extremes in temperature and drought, however, are more of a threat to the survival of this species [ 37 ].

BOTANICAL AND ECOLOGICAL CHARACTERISTICS SPECIES: Carnegiea gigantea GENERAL BOTANICAL CHARACTERISTICS : Saguaro is a native, arborescent, stem succulent that grows from 9.8 to 52.5 feet (3-16 m) tall and 5.9 to 29.5 inches (5-75 cm) in diameter [ 6 , 10 , 64 , 65 ]. It is the largest of the columnar cacti growing in the United States [ 89 ]. Saguaro has a deep anchoring taproot (up to 3.2 feet [1 m] deep) and extensive lateral roots (13 to 98 feet [4-30 m] long) [ 14 , 65 ]. The stems are simple with one to five (rarely up to 49) lateral, erect branches [ 6 , 10 ]. Saguaro trunks have many prominent ribs, armed with dense, stout spines that are up to 2.8 inches (7 cm) long [ 6 , 10 , 32 ].

Flowers are 3.4 to 4.9 inches (8.7-12.5 cm) long and occur at the ends of branches [ 6 , 32 , 45 ]. Fruits are oblong and contain up to 2,500 seeds [ 1 , 10 ]. RAUNKIAER LIFE FORM : Stem succulent REGENERATION PROCESSES : Saguaro reproduce sexually and are self-incompatible [ 2 ]. Reproduction begins when a plant is approximately 7.2 feet (2.2 m) tall [ 29 , 68 ]. Growth is extremely slow [ 47 , 68 ]. At the end of 2 years, seedlings will be about 0.25 inch (0.6 cm) tall [ 10 ]. At 3.2 feet (1 m), plants may be 20 to 50 years old [ 47 ]. Flowers only develop at branch and main stem tips. An increase in branch number increases the reproductive potential of an individual [ 37 ].

Many different animals pollinate the nocturnally blooming saguaro flowers and are detailed elsewhere [ 2 , 39 , 40 ]. Flowers are open for less than 24 hours [ 2 ]. A plant averages four open flowers per day for about 30 days [ 39 ]. Plants commonly have more than 100 fruits [ 47 , 68 ]. Seeds germinate readily [ 10 ]. Conditions for germination are detailed elsewhere [ 1 , 89 , 91 ]. Saguaro seeds are short-lived; seed reserves are not maintained in the soil [ 58 , 76 ]. In random soil samples, relative densities of saguaro seeds were between 0.3 and 2.0 percent [ 56 ]. Less than 1 percent of the annual seed production germinates due to predation or moisture stress [ 15 , 48 ]. Heavy seedfall can occur during the summer rains [ 68 ]. Drought during the 12 to 14 months following germination is the most critical factor threatening seedling survival [ 48 , 67 ].

Perennial shrubs, such as foothills paloverde (Cercidium microphyllum), are important as nurse plants for facilitating saguaro establishment [ 22 , 29 , 36 , 62 ]. Seed dispersal by frugivorous birds is a primary factor in saguaro establishment beneath shrub canopies [ 36 ]. Saguaro seedling density significantly (p<0.05) decreased from the center to the outer edges of nurse plant canopies [ 29 ]. On the margins of its range, recruitment has not kept pace with mortality caused by freezing temperatures and drought [ 52 , 76 ]. Saguaro has lower fruit production at the drier western edge of its range [ 52 ]. In some areas where cattle grazing has not occurred, recruitment appeared to occur in pulses correlated with above-normal precipitation [ 76 ]. SITE CHARACTERISTICS : Compared to other columnar cacti, saguaro occurs over the broadest range of habitats from gently sloping alluvial flats of the lower bajadas to steep, rocky, high-elevation volcanic slopes [ 51 , 53 , 74 ].

The greatest densities of saguaro are found in the more mesic eastern parts of its range [ 37 ]. Saguaro occurs on shallow soils that are light, coarse-textured, and rocky. The soils are underlain at 3.2 to 9.6 feet (1-3 m) depths by an impervious caliche layer [ 8 , 88 ]. There is usually no differentiation of the soil into horizons [ 87 , 88 ]. Saguaro is found at elevations from 1,640 to 5,000 feet (500-1,525 m) [ 35 , 50 , 56 , 86 ]. Saguaro has been reported on all aspects [ 77 , 88 ]. However, most individuals occur on open east- and west-facing slopes, and the fewest occur on north-facing slopes [ 6 , 77 , 86 ]. The Sonoran Desert is a warm desert with a semiarid to arid continental or an arid subtropical climate [ 27 , 67 , 82 ].

Precipitation is bimodal, falling December to February and July to August, and amounts vary from year to year [ 19 , 42 , 51 ]. Average amounts of rain per year are 6 to 15 inches (152-400 mm) [ 3 , 14 , 42 , 84 ]. Common arborescent associated species are Organ Pipe Cactus (Lemierocereus thurberi), barrelcactus (Ferocactus wislizeni), cholla (Opuntia spp.), ocotillo (Fouqueria splendens), catclaw acacia (Acacia greggii), ironwood (Olneya tesota), and jojoba (Simmondsia chinensis) [ 8 , 13 , 26 , 50 ].

Other associated species are littleleaf krameria (Krameria parvifolia), fluffgrass (Erioneuron pulchellum), tobosa (Hilaria mutica), Indian-wheat (Plantago insularis), and thelypody (Thelypodium lasiophyllum) [ 13 , 23 , 61 ]. SUCCESSIONAL STATUS : Obligate Climax Series Succession in desert systems is difficult to define [ 36 ]. Saguaro may be considered a climax species. Establishing in the shade of perennial shrubs, saguaro usually outlives and surpasses the nurse plants. Regeneration of saguaro continues in suitable areas of its range. SEASONAL DEVELOPMENT : Saguaro flowers from late April to June [ 1 , 32 , 39 , 45 ]. Fruits mature during June and July before the summer rains [ 6 , 65 ]. Most growth of saguaro occurs during the summer rainy season [ 6 ].

FIRE ECOLOGY SPECIES: Carnegiea gigantea FIRE ECOLOGY OR ADAPTATIONS : Saguaro is not truly adapted to fire because there is no postfire stimulation of flowering or seed production [ 73 ]. It has several prominent morphological characteristics, however, that may aid its survival when burned. The apex is protected to some degree by tissue folds and spines. Vascular tissue is protected by a thick cortex that has a high thermal capacity close to that of water. As saguaro ages, ribs at the base of a plant may develop a woody bark which is more resistant to burning than young tissue [ 73 ]. Although mortally injured by fire, death may be delayed if the saguaro can live off of its reserves, which may enable a plant to flower for 1 to 6 years more [ 73 ]. Singed saguaro have been observed to flower from unburned branches. However, scorched plants may die due to reduced vigor [ 58 ]. Fire may remove spines from a saguaro, making it vulnerable to herbivory [ 73 ]. Nurse plant species influence saguaro fire survival.

Although desert fire temperatures are variable, fire temperatures beneath foothills paloverde were lower than under triangleleaf bursage (Ambrosia deltoidea) [ 16 ]. Fire-free periods in the Sonoran Desert are greater than 250 years [ 73 ]. Saguaro would be eliminated under a fire frequency of less than 30 years [ 58 ]. Fires that do occur are usually of low intensity due to small fuel loads [ 41 ]. FIRE REGIMES : Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find Fire Regimes". POSTFIRE REGENERATION STRATEGY : Tree without adventitious-bud root crown Secondary colonizer - off-site seed FIRE EFFECTS SPECIES: Carnegiea gigantea IMMEDIATE FIRE EFFECT ON PLANT : Fire top-kills saguaro, and it may kill existing seedlings [ 73 ]. Because there is a lag time between time of injury by fire and time of death, postfire mortality may be underestimated [ 58 ].

Small saguaro, less than 6.6 to 13 feet (2-4 m) tall, with large amounts of fuel at the plant base do not survive. Larger saguaro may survive with limited damage [ 16 , 41 ]. DISCUSSION AND QUALIFICATION OF FIRE EFFECT : NO-ENTRY PLANT RESPONSE TO FIRE : Postfire recovery is dependent upon individual plant recovery and seed dispersal from unburned plants [ 58 ]. Surviving saguaro with little or no injury will resume growth [ 16 ]. Absorption of rain following fire-caused injuries can result in fire scars splitting, which opens the plant to insects and infections [ 73 ]. Vegetation surveys done the third and fourth years following an early summer fire found no sprouting of saguaro and no seedlings [ 59 ]. Two studies that compared burn and adjacent wildfire areas 2 years after prescribed burning found that 100 percent of saguaro present in plots had died. Plots were read before and after fire. There were no sprouts or seedlings [ 16 , 17 ].

DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : NO-ENTRY FIRE MANAGEMENT CONSIDERATIONS : Fire would be an effective tool to control saguaro invasion or density [ 68 , 73 ]. Along major highways in Arizona, motorist-caused fires have completely eliminated the saguaro over large areas [ 58 ]. REFERENCES SPECIES: Carnegiea gigantea 1 . Alcorn, Stanley M.; Martin, S. Clark. 1974. Cereus giganteus Engelm. saguaro. In: Schopmeyer, C. S., technical coordinator. Seeds of woody plants in the United States. Agric. Handb. 450. Washington, DC: U.S. Department of Agriculture, Forest Service: 313-314. [7584] 2 . Alcorn, Stanley M.; McGregor, S. E.; Olin, George. 1961. Pollination of saguaro cactus by doves, nectar-feeding bats, and honey bees. Science. 133: 1594-1595. [5095] 3 .

Asplund, Kenneth K.; Gooch, Michael T. 1988. Geomorphology and the distributional ecology of Fremont cottonwood (Populus fremontii) in a desert riparian canyon. Desert Plants. 9(1): 17-27. [563] 4 . Baisan, Christopher H.; Swetnam, Thomas W. 1990. Fire history on a desert mountain range: Rincon Mountain Wilderness, Arizona, U.S.A. Canadian Journal of Forest Research. 20: 1559-1569. [14986] 5 . Bennett, Peter S.; Kunzmann, Michael R.; Johnson, R. Roy. 1989. Relative nature of wetlands: riparian and vegetational considerations. In: Abell, Dana L., technical coordinator. Protection, management, and restoration for the 1990's: Proceedings of the California riparian systems conference; 1988 September 22-24; Davis, CA. Gen. Tech. Rep. PSW-110. Berkeley, CA: U.S.

Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station: 140-142. [13516] 6 . Benson, Lyman. 1982. The cacti of the United States and Canada. Stanford, CA: Stanford University Press. 1044 p. [1513] 7 . Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals, reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's associations for the eleven western states. Tech. Note 301. Denver, CO: U.S. Department of the Interior, Bureau of Land Management. 169 p. [434] 8 . Blydenstein, John; Hungerford, C. Roger; Day, Gerald I.; Humphrey, R. 1957. Effect of domestic livestock exclusion on vegetation in the Sonoran Desert. Ecology. 38(3): 522-526. [4570] 9 . Bock, Carl E.; Bock, Jane H. 1990.

Effects of fire on wildlife in southwestern lowland habitats. In: Krammes, J. S., technical coordinator. Effects of fire management of Southwestern natural resources: Proceedings of the symposium; 1988 November 15-17; Tucson, AZ. Gen. Tech. Rep. RM-191. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 50-64. [11273] 10 . Britton, N. L.; Rose, J. N. 1920. The cactaceae. New York: Dover Publications, Inc. 4 vols. [21017] 11 . Brown, David E.; Lowe, Charles H.; Hausler, Janet F. 1977. Southwestern riparian communities: their biotic importance and management in Arizona. In: Johnson, R. Roy; Jones, Dale A., tech. coords. Importance, preservation and management of riparian habitat: a symposium: Proceedings; 1977 July 9; Tucson, AZ. Gen. Tech. Rep. RM-43.

Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment 201-211. [5348] 12 . Brush, Timothy; Anderson, Bertin W.; Ohmart, Robert D. 1983. Habitat selection related to resource availability among cavity- nesting birds. In: Davis, Jerry W.; Goodwin, Gregory A.; Ockenfeis, Richard A., technical coordinators. Snag habitat management: proceedings of the symposium; 1983 June 7-9; Flagstaff, AZ. Gen. Tech. Rep. RM-99. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 88-98. [17820] 13 . Buchmann, Stephen L. 1987. Floral biology of jojoba (Simmondsia chinensis), an anemophilous plant. Desert Plants. 8(3): 111-124. [5245] 14 . Cannon, William Austin. 1911.

The root habits of desert plants. Washington, DC: The Carnegie Institution of Washington. 96 p. [5003] 15 . Castellanos, A. E.; Molina, F. E. 1990. Differential survivorship and establishment in Simmondsia chinensis (jojoba). Journal of Arid Environments. 19: 65-76. [14982] 16 . Cave, George Harold, III. 1982. Ecological effects of fire in the upper Sonoran Desert. Tempe, AZ: Arizona State University. 124 p. Thesis. [12295] 17 . Cave, George H.; Patten, Duncan T. 1984. Short-term vegetation responses to fire in the upper Sonoran Desert. Journal of Range Management. 37(6): 491-496. [610] 18 . Cornejo, Dennis O.; Leigh, Linda S.; Felger, Richard S.; Hutchinson, Charles F. 1982. Utilization of mesquite in the Sonoran Desert: past and future.

In: Parker, Harry W., editor. Mesquite utilization 1982: Proceedings of the symposium; 1982 October 29-30; Lubbock, TX. Lubbock, TX: Texas Tech University, College of Agricultural Sciences: Q-1-Q-20. [5457] 19 . Eddy, Thomas A. 1961. Foods and feeding patterns of the collared peccary in southern Arizona. Journal of Wildlife Management. 25: 248-257. [9888] 20 . Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [905] 21 . Felger, R. S. 1977. Mesquite in Indian cultures of southwestern North America. In: Simpson, B. B., ed. Mesquite: Its biology in two desert ecosystems. US/IBP Synthesis 4. Stroudsburg, PA: Dowden, Hutchinson & Ross, Inc: 150-176.

[5195] 22 . Franco, A. C.; Nobel, P. S. 1989. Effect of nurse plants on the microhabit and growth of cacti. Journal of Ecology. 77: 870-886. [9766] 23 . Frost, William E.; Smith, E. Lamar. 1991. Biomass productivity and range condition on range sites in southern Arizona. Journal of Range Management. 44(1): 64-67. [14974] 24 . Ganter, Philip F.; Starmer, William T.; Lachance, Marc-Andre; Phaff, Herman J. 1986. Yeast comm. from host plants & associated Drosophila in s. AZ: new isolations & analy. of the rela. imp. of hosts & vectors on comm. comp. Oecologia. 70: 386-392. [5131] 25 . Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; [and others]. 1977.

Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. [998] 26 . Gentry, Howard Scott. 1958. The natural history of jojoba (Simmondsia chinensis) and its cultural aspects. Economic Botany. 12(3): 261-295. [4917] 27 . Goldberg, Deborah E.; Turner, Raymond M. 1986. Vegetation change and plant demography in permanent plots in the Sonoran Desert. Ecology. 67(3): 695-712. [4410] 28 . Hastings, James Rodney; Alcorn, Stanley M. 1961. Physical determinations of growth and age in the giant cactus. Journal of the Arizona Academy of Science. 2: 32-39. [5094] 29 . Hutto, Richard L.; McAuliffe, Joseph R.; Hogan, Lynee. 1986.

Distributional associates of the saguaro (Carnegiea gigantea). Southwestern Naturalist. 31(4): 469-476. [1229] 30 . Johnson, Hyrum B. 1976. Vegetation and plant communities of southern California deserts--a functional view. In: Latting, June, ed. Symposium proceedings: plant communities of southern California; 1974 May 4; Fullerton, CA. Special Publication No. 2. Berkeley, CA: California Native Plant Society: 125-164. [1278] 31 . Johnson, R. Roy; Haight, Lois T.; Riffey, Meribeth M.; Simpson, James M. 1980. Brushland/steppe bird populations. In: DeGraaf, Richard M., technical coordinator. Management of western forests and grasslands for nongame birds: Workshop proceedings; 1980 February 11-14; Salt Lake City, UT. Gen. Tech. Rep. INT-86. Ogden, UT: U.S.

Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station: 98-112. [17900] 32 . Kearney, Thomas H.; Peebles, Robert H.; Howell, John Thomas; McClintock, Elizabeth. 1960. Arizona flora. 2d ed. Berkeley, CA: University of California Press. 1085 p. [6563] 33 . Krausman, Paul R.; Ordway, Leonard L.; Whiting, Frank M.; Brown, William H. 1990. Nutritional compostition of desert mule deer forage in the Picacho Mountains, Arizona. Desert Plants. 10(1): 32-34. [7259] 34 . Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation of the conterminous United States. Special Publication No. 36. New York: American Geographical Society. 77 p. [1384] 35 . Lowe, Charles H.; Holm, Peter A. 1991.

The amphibians and reptiles at Saguaro National Monument, Arizona. Technical Report No. 37. Tucson, AZ: University of Arizona, School of Renewable Natural Resources, Cooperative National Park Resources Study Unit. 20 p. [18335] 36 . McAuliffe, Joseph R. 1988. Markovian dynamics of simple and complex desert plant communities. American Naturalist. 131(4): 459-490. [6744] 37 . McAuliffe, Joseph R.; Janzen, Fredric J. 1986. Effects of intraspecific crowding on water uptake, water storage, apical growth, and reprod. potential in the Sahuaro cactus, Carnegiea gigantea. Botanical Gazette. 147(3): 334-341. [5289] 38 . McCulloch, Clay Y. 1973. Part I: Seasonal diets of mule and white-tailed deer. In: Deer nutrition in Arizona chaparral and desert habitats. Special Report No. 3.

Phoenix, AZ: Arizona Game and Fish Department: 1-37. [9894] 39 . McGregor, S. E.; Alcorn, Stanley M.; Kurtz, Edwin B., Jr.; Butler, George D., Jr. 1959. Bee visitors to Saguaro flowers. Journal of Economic Entomology. 52(5): 1002-1004. [5092] 40 . McGregor, S. E.; Alcorn, Stanley M.; Olin, George. 1962. Pollination and pollinating agents of the saguaro. Ecology. 43(2): 259-267. [5091] 41 . McLaughlin, Steven P.; Bowers, Janice E. 1982. Effects of wildfire on a Sonoran Desert plant community. Ecology. 63(1): 246-248. [1619] 42 . McLaughlin, Steven P.; Bowers, Janice E. 1990.

A floristic analysis and checklist for the northern Santa Rita Mountains, Pima Co., Arizona. Southwestern Naturalist. 35(1): 61-75. [11113] 43 . Meents, Julie K.; Anderson, Bertin W.; Ohmart, Robert D. 1984. Sensitivity of riparian birds to habitat loss. In: Warner, Richard E.; Hendrix, Kathleen M., eds. California riparian systems: Ecology, conservation, and productive management: Proceedings of a conference; 1981 September 17-19; Davis, CA. Berkeley, CA: University of California Press: 619-625. [5864] 44 . Miller, Gary D.; Gaud, William S. 1989. Composition and variability of desert bighorn sheep diets. Journal of Wildlife Management. 53(3): 597-606. [14429] 45 . Munz, Philip A. 1973. A California flora and supplement. Berkeley, CA: University of California Press. 1905 p.

[6155] 46 . Niering, William A.; Lowe, Charles H. 1984. Vegetation of the Santa Catalina Mountains: community types and dynamics. Vegetatio. 58: 3-28. [12037] 47 . Niering, W. A.; Whittaker, R. H.; Lowe, C. H. 1963. The saguaro: a population in relation to environment. Science. 142(3588): 15-23. [5093] 48 . Nobel, Park S. 1988. Environmental biology of agaves and cacti. New York: Cambridge University Press. 270 p. [12163] 49 . Olsen, Ronald W. 1973. Shelter-site selection in the white-throated woodrat, Neotoma albigula. Journal of Mammalogy. 54: 594-610. [9886] 50 . Parker, Kathleen C. 1986.

Partitioning of foraging space and nest sites in a desert shrubland bird community. American Midland Naturalist. 115(2): 255-267. [19258] 51 . Parker, Kathleen C. 1988. Environmental relationships and vegetation associates of columnar cacti in the northern Sonoran Desert. Vegetatio. 78: 125-140. [6953] 52 . Parker, Kathleen C. 1989. Height structure and reproductive characteristics of senita, Lophocereus schottii (Cactaceae), in southern Arizona. Southwestern Naturalist. 34(3): 392-401. [9285] 53 . Parker, Kathleen C. 1991. Topography, substrate, and vegetation patterns in the northern Sonoran Desert. Journal of Biogeography. 18: 151-163. [14979] 54 . Raunkiaer, C. 1934. The life forms of plants and statistical plant geography.

Oxford: Clarendon Press. 632 p. [2843] 55 . Rea, Amadeo M. 1991. Gila River Pima dietary reconstruction. Arid Lands Newsletter. 31: 3-10. [18255] 56 . Reichman, O. J. 1975. Relation of desert rodent diets to available resources. Journal of Mammalogy. 56(4): 731-751. [4572] 57 . Robinett, Dan. 1990. Tohono O'odham range history. Rangelands. 12(6): 296-300. [14968] 58 . Rogers, Garry F. 1985. Mortality of burned Cereus giganteus. Ecology. 66(2): 630-631. [2020] 59 . Rogers, Garry F.; Steele, Jeff. 1980. Sonoran Desert fire ecology.

In: Stokes, Marvin A.; Dieterich, John H., technical coordinators. Proceedings of the fire history workshop; 1980 October 20-24; Tucson, AZ. Gen. Tech. Rep. RM-81. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 15-19. [16036] 60 . Scarbrough, David L.; Krausman, Paul R. 1988. Sexual segregation by desert mule deer. Southwestern Naturalist. 33(2): 157-165. [5250] 61 . Shantz, H. L.; Piemeisel, R. L. 1924. Indicator significance of the natural vegetation of the Southwestern desert region. Journal of Agricultural Research. 28(8): 721-803. [12222] 62 . Sherbrooke, Wade C. 1989.

Seedling survival and growth of a Sonoran Desert shrub, jojoba (Simmondsia chinensis), during the first 10 years. Southwestern Naturalist. 34(3): 421-424. [9284] 63 . Short, Henry L. 1979. Deer in Arizona and New Mexico: their ecology and a theory explaining recent population decreases. Gen. Tech. Rep. RM-70. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 25 p. [4489] 64 . Shreve, Forrest. 1942. The desert vegetation of North America. Botanical Review. 8(4): 195-246. [5051] 65 . Shreve, F.; Wiggins, I. L. 1964. Vegetation and flora of the Sonoran Desert. Stanford, CA: Stanford University Press. 2 vols. [21016] 66 .

Starmer, William T.; Phaff, Herman J.; Bowles, Jane M.; Lachance, Marc-Andre. 1988. Yeasts vectored by insects feeding on decaying saguaro cactus. Southwestern Naturalist. 33(3): 362-363. [6580] 67 . Steenbergh, Warren F.; Lowe, Charles H. 1976. Ecology of the saguaro: I. The role of freezing weather in a warm-desert plant population. In: Research in the Parks: Transactions of the National Park Centennial symposium; 1971 December 28-29. National Park Service Symposium Series No. 1. Washington, DC: U.S. Department of the Interior: 49-92. [5209] 68 . Steenbergh, Warren F.; Lowe, Charles H. 1977. Ecology of the saguaro: II. Reproduction, germination, establishment, and survival of the young plant. National Park Service Scientific Monograph Series Number 8. Washington, DC: U.S. Department of the Interior, National Park Service.

242 p. [5211] 69 . Kettle, W. Dean; Fitch, Henry S. 1983. Field research and prairie investigations at the University of Kansas. In: Kucera, Clair L., ed. Proceedings of the 7th North American prairie conference; 1980 August 4-6; Springfield, MO. Columbia, MO: University of Missouri: 107-112. [3212] 70 . Stickney, Peter F. 1989. Seral origin of species originating in northern Rocky Mountain forests. Unpublished draft on file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT; RWU 4403 files. 7 p. [20090] 71 . Taylor, Alan R. 1974. Ecological aspects of lightning in forests. In: Proceedings, annual Tall Timbers fire ecology conference; 1973 March 22-23; Tallahassee, FL. No. 13.

Tallahassee, FL: Tall Timbers Research Station: 455-482. [16663] 72 . Taylor, Alan R. 1974. Forest fire. In: McGraw-Hill Yearbook of Science and Technology. New York: McGraw-Hill Book Company, Inc: ?. [17221] 73 . Thomas, P. A. 1991. Response of succulents to fire: a review. International Journal of Wildland Fire. 1(1): 11-22. [14991] 74 . Tomoff, Carl S. 1974. Avian species diversity in desert scrub. Ecology. 55: 396-403. [19307] 75 . Turner, Raymond M. 1982. Mohave desertscrub. In: Brown, David E., ed. Biotic communities of the American Southwest--United States and Mexico. Desert Plants. 4(1-4): 157-168. [2374] 76 . Turner, Raymond M.

1990. Long-term vegetation change at a fully protected Sonoran Desert site. Ecology. 7(2): 464-477. [10866] 77 . Turner, Raymond M.; Bowers, Janice E. 1988. Long-term changes in populations of Carnegiea gigantea, exotic plant spp. & Cercidium floridum at the Desert Lab, Tumamoc, Tucson, Arizona. In: Whitehead, E. E.; [and others], eds. Arid lands: Proceedings of the conference; 1985; Tucson, AZ. [Place of publication unknown]: Westview Press: 445-455. [15007] 78 . Turner, Raymond M.; Brown, David E. 1982. Sonoran desertscrub. In: Brown, David E., ed. Biotic communities of the American Southwest--United States and Mexico. Desert Plants. 4(1-4): 181-221. [2375] 79 . Urness, Philip J. 1973.

Part II: Chemical analyses and in vitro digestibility of seasonal deer forages. In: Deer nutrition in Arizona chaparral and desert habitats. Special Report 3. Phoenix, AZ: Arizona Game and Fish Department: 39-52. [93] 80 . Urness, P. J.; McCulloch, C. Y. 1973. Part III: Nutritional value of seasonal deer diets. In: Special Report 3. Deer nutrition in Arizona chaparral and desert habitats. Phoenix, AZ: Arizona Game and Fish Department: 53-68. [12223] 81 . U.S. Department of Agriculture, Soil Conservation Service. 1982. National list of scientific plant names. Vol. 1. List of plant names. SCS-TP-159. Washington, DC. 416 p. [11573] 82 . Villa-Salas, Avelino B.; Manon-Garibay, A. Cecilia. 1980. Multiresource management research in northern Sonora.

In: IUFRO/MAB conference: research on multiple use of forest resources: Proceedings; 1980 May 18-23; Flagstaff, AZ. Gen. Tech. Rep. WO-25. Washington, DC: U.S. Department of Agriculture, Forest Service: 20-25. [15925] 83 . Wallmo, Olof C. 1975. Important game animals and related recreation in arid shrublands of the United States. In: Hyder, D. N., ed. Arid shrublands: Proceedings, 3rd workshop of the United States/Australia Rangelands Panel; 1973 March 26-April 5; Tuscon, AZ. Denver, CO: Society for Range Management: 98-107. [2446] 84 . Warren, Peter L.; Anderson, L. Susan. 1985. Gradient analysis of a Sonoran Desert wash. In: Johnson, R. Roy; [and others], technical coordinators.

Riparian ecosystems & their mgmt: reconciling conflicting issues: Proceedings, 1st North American riparian conference; 1985 April 16-18; Tucson, AZ. Gen. Tech. Rep. RM-120. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 150-155. [17158] 85 . Wells, Philip V. 1974. Post-glacial origin of the present Chihuahuan Desert less than 11,500 years ago. In: Wauer, Roland H.; Riskind, David H., eds. Transactions of the symposium on the biological resources of the Chihuahuan Desert region, United States and Mexico; 1974 October 17-18; Alpine, TX. Transactions and Proceedings Series No. 3. Washington, DC: U.S. Department of the Interior, National Park Service: 67-83. [16056] 86 . Whittaker, R. H.; Niering, W. A. 1965.

Vegetation of the Santa Catalina Mountains, Arizona: a gradient analysis of the south slope. Ecology. 46: 429-452. [9637] 87 . Yang, Tien Wei; Lowe, Charles H., Jr. 1955. Correlation of major vegetation climaxes with soil characteristics in the Sonoran Desert. Science. 123: 542. [12226] 88 . Yeaton, Richard I.; Travis, J.; Gilinsky, Ellen. 1977. Competition and spacing in plant communities: the Arizona upland association. Journal of Ecology. 65: 587-595. [4193] 89 . Young, James A.; Young, Cheryl G. 1986. Collecting, processing and germinating seeds of wildland plants. Portland, OR: Timber Press. 236 p. [12232] 90 . Anon. 1992. King of cactuses. National Geographic. 182(5): [Pages unknown]. [19916] 91 . Heit, C.

E. 1970. Laboratory germination of barrel and saguaro cactus seed. Ass. Off. Seed Anal. News Letter. 44(4): 11-15. [21019] Latin: (Carnegiea gigantea) Saguaros are the most spectacular of our native Southwestern cacti. On the top shelf in my little hobby greenhouse grows a giant. Though this giant is only 5 years old and, for now at least, 4 inches tall, it has the potential to get much larger. The plant is the saguaro cactus from the Sonoran Desert of Arizona. The saguaro cactus (Carnegiea gigantea) is a superstar amongst the cactus family both for its storied existence and size. It can reach as much as 45 feet in height though 20 to 30 feet specimens with foot thick trunks are more common. During the first 75 years of its life, it grows as an unbranched column; thereafter it begins to branch and forms the familiar shape we know. Saguaros often live to be 150 years old.

This cactus grows only in the Sonoran Desert, the driest desert in the United States that occupies 120,000 square miles of the southwestern quarter of Arizona, and adjacent areas in California, the state of Sonora in Mexico and parts of the Baja Peninsula. It occurs in areas receiving between 2 and 10 inches of rainfall per year but won’t grow in salty soils or along arroyos where floods might occur. While it tolerates frost it won’t survive where freezing conditions prevail. Saguaro stems have 20 or more ribs armed with clusters of stout thorns. The pleated arrangement of the cactus body allows it to expand when rainfall is plentiful and shrink during dry spells. In the spring the ends of the branches wear a topknot of showy white flowers. Flowering begins when plants reach about 50 years of age. The name saguaro is a Spanish language adaptation of the name used by the Tohono O’odham tribe that inhabited the region prior to European settlement. The Latin name honors Andrew Carnegie, the steel magnate and philanthropist who provided funds for so many libraries around the nation in the early years of the 20th century.

Saguaro was described in 1848 as Cereus giganteus by St. Louis botanist George Englemann, but the cacti specialists from the New York Botanical Garden - Britton and Rose - reclassified it in 1908. Carnegie, who was funding much of their research, was invited to Tucson for the big announcement but lost interest quickly when he was informed it was only a name change, not a new kind of cactus. Saguaros, for all their size and toughness, live a fragile existence. As with all plants in fragile environments, humans are their biggest threat. Because they are so slow growing and they occur in such remote areas theft is a major concern. Arizona has enacted laws preventing collection from public lands and requires an extensive paper trail to follow all wild-collected saguaros. In an attempt to cut down on cactus rustling, RFD chips have been implanted to aid in the tracking operation. Though they live a precarious existence sometimes they strike back to extract revenge for mistreatment. Cactus plugging - a highly illegal but still common practice of pumping a cactus body full of lead by armed and drunken marauders - usually results in a dead cactus.

But in February of 1982, David Grundman arrived with his shotgun for a bit of merriment but left in a hearse. Though this incident sounds like an urban legend, especially after the Austin Lounge Lizards immortalized it in their song, "Saguaro," it really happened. Apparently Grundman blasted most of the way through the trunk of a 125-year-old cactus, but it refused to fall. So, to speed things along he took a saguaro rib from a dead plant and poked at one of its giant arms. The 500-pound arm detached and fell on the hapless gunman. Then the main trunk, made unstable by the loss of one of its arms, also toppled, falling directly on top of Grundman and as the Lizards tell us "smashed him like a bug." Saguaro seeds are produced in abundance and are readily available. Though it is easy to grow from seed, cultivation only marginally speeds its slow growth rate. The best way to enjoy these beauties is to see them in their native habitat where they can be seen in their full grandeur.

By: Gerald Klingaman, retired Extension News - December 12, 2008 The University of Arkansas Division of Agriculture does not maintain lists of retail outlets where these plants can be purchased. Please check your local nursery or other retail outlets to ask about the availability of these plants for your growing area. Cacti / Desert Succulents - Saguaro National Park (U.S. National Park Service) Cacti / Desert Succulents Cacti / Desert Succulents Cacti / Desert Succulents Saguaro National Park is home to 25 species of cactus ranging from the towering saguaro cactus (Carnegiea gigantea) to the tiniest type of cactus in the park, the mammillaria (Mammillaria spp).

The most common cacti species at Saguaro National Park and within Tucson, Arizona include: Saguaro cactus (Carnegiea gigantea) Saguaro Saguaro (Carnegiea gigantea) Main Sources: Dimmitt, Mark, "Cactaceae", in Steven Phillips and Patricia Comus, eds., 2000, A Natural History of the Sonoran Desert, pp.84-93, Arizona-Sonora Desert Museum Press, Tucson; Crosswhite, Frank, 1980, "The annual saguaro harvest and crop cycle of the Papago, with reference to ecology and symbolism", Desert plants 2:1:3-62; Epple, Ann, 1995, A Field Guide to the Plants of Arizona, pp. 157-8, Lew Anne Publishing Co., Mesa AZ; Hodgson, Wendy, Food Plants of the Sonoran Desert. Our lands are remarkably rich in this largest, columnar cactus to be found in the United States.

Young saguaros cannot survive either intense desert sunlight or trampling, so typically survivors begin growth under a "nurse" plant (palo verde, acacia, mesquite, creosote bush), growing about 1/2" in the first year and to 1' in about 15 years. (That its early vertical growth is slow is related to priority investment in expansion of the root system.) As the plant grows larger, its white-gray spines begin to provide protective shade for the trunk. In 40 to 50 years, saguaros reach about 10' tall (and first begin to flower and produce fruit), and in 75 to 100 years they may sprout arm buds, at heights of 12 to 20: here is a set just beginning to form, on a plant just north of the Trail Tank, seen in September 2004: (Click on the image below to see the whole plant.) Saguaros may reach a height of 60', weigh as much as 9 tons, and reach ages of over 200 years (See below for some examples.).

The great upright stem of this cactus is strengthened by an interior cylinder of wooden "ribs". The pale green, columnar trunk has pleats which enable the plant to swell and shrink like an accordion depending on rains. A mature saguaro may soak up 200 gallons during a rainstorm, only gradually transpiring its supply over long periods of drought (see images below). It can tolerate cold to below freezing, provided the duration of such temperatures is brief -- less than 24 hours. (This explains why most saguaros in our area are found on south-facing slopes, and why around 4,000' elevation is its upper limit in our area. The northern- and higher-elevation-limits of this temperature constraint marks the limits of our Sonoran Desert, as set by the distribution of this plant.) Saguaros grow to maturity best on sloping, coarse soils, since their roots require good drainage and soil aeration. The skin of a saguaro is covered with a thick, waxy cuticle which waterproofs the surface and restricts water vapor loss to the stomates (pores provided for gas exchange).

The pleats have areoles, roundish pads distributed about 1" apart and from which the spines (8-30 per areole) protrude. Spines are important not only for defense from herbivores but also for shading, thus cooling the trunk. Immediately beneath the skin is a thin layer of chlorophyll-containing cells which do most of the photosynthesis for the plant. Most of the plant's bulk is water storage tissue (which also prevents overheating -- it absorbs heat during the day and releases it at night). The root system is shallow (aside from one tap root extending more than 2' down), but it radiates out about as far as the plant is tall, and thus eventually robs its nurse plant of moisture, eventually killing it. Growth of the above-ground plant accelerates over time, as its roots are able to absorb moisture from the briefest and lightest of rains.

Botanists formerly thought that the presence of extensive stands of Saguaros only of a particular age was evidence of some kind of regional climatic, disease- or human-caused change -- for example, the presence of only old Saguaros in an area of Saguaro National Park reflected a long-term decline of the plant in that area. But more recent evidence suggests that Saguaro seeds germinate and survive in considerable numbers rather rarely, only after unusually propitious weather conditions facilitate this in particular locales. As Dimmitt (p. 188) suggests, such survival requires "several consecutive years of milder and wetter-than-average weather", conditions which occur in the various parts of the Arizona Uplands "only a few times a century." In parts of Saguaro Juniper and continguous lands, we have large numbers of rather young Saguaros, indeed on one small terrace in Lower Hot Springs Canyon one can see groupings (of six, nine, and a baker's dozen respectively) of very small plants rising up protected underneath three different nurse trees.

(See below for a view of 13 young saguaros under a Palo Verde.) While this profusion may indeed reflect a gradual spreading of Saguaros into our area, it more definitely points to a recent period of propitious rainfall at this particular location. In another location (a wash slope of Soza Mesa), we see a situation where a large saguaro has grown to dwarf its former nurse, and has also spawned a next-generation nursling: (click on the image for a closeup of the plant's base) Only when saguaro plants first germinate do they have leaves, as shown in this photo where the tiny sprouts are compared in size to a Lincoln penny: (Click on the image to enlarge it) The seedlings are extremely vulnerable at first, and only those protected by nurse plants (which provide shelter and protection from herbivores -- from mice to birds) are likely to survive. Growth rate is very slow at first, plants attaining perhaps 1 1/2 inches in height after 10 years, perhaps 2 feet tall in 30 years.

Saguaros begin to flower in our area between 40 and 50 years, when they are around 8 feet tall (Dimmitt, p. 188). Waxy-white and funnel-shaped flowers bloom in May to June, opening at night (this is a plant of the Cereus family) and remaining open part of the following day (each individual flower blooming for only one day). A mature plant may produce 200 flowers per year, a few opening each day. Bats and moths pollinate them at night, diverse insects by day. (The Cactus Bees appear to be crucial pollinators in our area.) The ovate, green fruits split open in late June and July, revealing their deep-red pulpy interiors, each fruit containing up to 2,000 tiny black seeds. A wide variety of creatures (including humans) enjoy the sweet pulp, seeds, and juice.

(See Saguaro fruit & processing for an account of the ripened fruit, its harvesting and processing.) In the photos at below right, the bloom has been split to show the interior structure: at the base, the ovary (which becomes the fruit), the central pistil, and the many stamens and petals surrounding it in radial symmetry. This is the most ancient type of flower form. (Click on the three right-hand images to enlarge.) Here (below) is a comparison of the Rabbit Ears Saguaro, located atop the hill of that name in Hot Springs Canyon, taken in 1993 and again in 2002. The growth of all four arms has been very considerable during the 9 year interval. In the June 1993 photo at left, the saguaro has almost completed its blooming, while in the May 2002 photo at right the blooms are just beginning. In June 1993 the plant was fairly full of water, while in May 2002 it shows the slendering effects of a long, almost unbroken winter drought.

(The plant on the right will have a rich blossoming and harvest despite this drought, since the effects of the immediately prior rainfall become apparent in fruiting only after a year has passed. A wet spring will be directly followed by a relatively poor harvest, as happened in the spring of 2004.) Here is a photo of the largest Saguaro we have seen in our area. (Let us know if you've seen a larger one!) It is located beside the Cascabel road just downhill from the Cascabel Community Center (the clerestory windows of which are visible behind this huge tree): We are reserving another page for reviewing the importance (both historical and contemporary) of saguaro fruit as a foodstuff -- see Saguaro fruit and processing . Below you will find further information on patterns of growth and decline.

The images below -- of a multi-armed Saguaro which fell sometime during the rains of late 2001 -- illustrate the shallowness (though not the spread -- many small roots broke off under the strain of collapse) of the root system: (Click on left-below image to enlarge) Collapses of this kind are almost always caused by a combination of wind and rain (when the root-holding ground has been softened by water and wind-gusts have been unusually strong) and usually destroy multi-armed saguaros rather than single-stalk plants (because the multi-armed trees display both greater top-heaviness and larger wind-catching surfaces). However, multiple arms in a mature saguaro also generate greater quantities of fruit production than are available to a single-stalked tree of similar height, a fact that apparently compensates for this greater structural vulnerability of size. On the other hand, many saguaros in our area die abruptly when struck by lightning, a fate which generally leaves the trunk standing.

Here are two examples, on the left, near the Red Tank in August of 2003, soon after a thunderstorm, and on the right, near the High Tank, photographed in April of 2004 (long after the event -- we are not entirely sure of the cause of this collapse): (Click on the left image to enlarge it.) Saguaros are prey to a variety of ills besides bad weather. For more discussion (and images) of Saguaro ailments, decline and demise, see this link: Saguaro Ailments, Death & Decay . Since 2002, Saguaro Juniper has joined with the Earlham Southwest Field Studies division of Earlham College (Richmond, Indiana) to conduct a census of a particular saguaro population in Hot Springs Canyon. For more details on the progress and results of this ongoing research, see the following link: Cristates bloom, just as the "normals" do. To the right, a cristate in lower Hot Springs Canyon, May 27, 2002. In the photo to the left, we see it from the south side, a great mass of saguaro flesh jutting out from the central pillar.

Below, close up, the mass resolves into an elaborate array of multiple fan-shaped forms, topped by the substantial twig nest of the hawk: .(Click on the images below to enlarge them.) To the left, another view from the north in somewhat softer light, showing the massive twig nest as well as the almost "barber-pole" spiraling quality of the saguaro arms themselves. And again to the left, a closeup of the massive nest on top. The exaggerated spiraling of the main upright arms was quite striking, shown below in two images taken under different light conditions. (Note also the cristate-tipped arm below far right.) Some years after 1995, this big Saguaro died a sudden death.

We neglected our opportunities to photograph the remnants until January of 2005, when we recorded this view below: (Click on the image for a close-up.) At the same time, we photographed the crystate shown above (in January 1995), now with a much better (and still) camera: (Click on the image for a close-up.) 10 Types Of Cactus To Grow At Home - Boldsky.com »10 Types Of Cactus To Grow At Home 10 Types Of Cactus To Grow At Home Published: Wednesday, January 2, 2013, 15:16 [IST] Subscribe to Boldsky Do you classify cactus as thorny plants that grow in desserts? Then you are missing out golden opportunities to decorate your home with different types of cactus. You can grow cactus plants in very aesthetic ways inside your home. In fact, there are many types of cactus that are very well suited for decorative purposes. Take the pincushion cactus for example. When this flowering cactus is in full bloom, it is breathtaking to behold. Moreover, it is very easy to grow cactus. Most types cactus are very low maintenance plants.

They do not need to watered often. They love bright sun shine and are hardy when it comes to tolerating climatic conditions. Also, cactus are basically wild plants. As a matter of fact, it is the wild types of cactus that are most beautiful. To grow cactus at home, you need some cuttings. Cactus plants mostly propagate vegetatively. The flowering cactus of course has a sensual way of propagation. Certain gigantic types of cactus like the Giant Saguaro can be cultivated as bonsais or restrained potted plants. The aesthetics that a cactus lends to your home is not comparable to any other houseplant. Here are some types of cactus that make great plants for your home decor. Pincushion Cactus This delicate type of cactus has such silky thorns that it closely resembles a pincushion. They grow in clusters and need no looking after at all. Beaver-tail Cactus The pad like structure of this cactus resembles a beaver's tail. It grows in patches and produces very colourful flowers. Ball Cactus This interesting species of cactus are shaped like perfect round thorny balls. They grow in clusters and look great as decorative houseplants.

These cactus doesn't like direct sunlight so keep then in partial shade. Rainbow Hedgehog Cactus They are the perfect houseplants due to their vibrantly coloured flowers. This cactus grows in clumps of oval shapes with the flowers on their head. Fairy Castle or Cereus tetragonus This cactus grows like a fairytale castle with some tall and some short towers. It is good as a fencing plant but can also be used as a potted plant. Haworthia Cactus Zebra This probably is the best cactus to grow indoors because it has high tolerance for low light conditions. The visual impact of its zebra crosses is a bonus. Cereus peruvianus This is rare variety of cactus that is not properly classified. However they grow quickly and flower without too much pampering. Giant Saguaro As the name rightly suggests, this is a very huge cactus plant. The branches of this cactus looks like outstretched arms. They make great corner plants owing to their size. Gymnocalycium A lovely flowering cactus that grows in isolation. You can cultivate them in small pots where space is scarce.

Echinopsis chamaecereus This is a cluster-forming cactus that flowers. The plant grows in tight coils that resemble a coiled snake.

Question: What type of plant is a saguaro?
Answer: CACTUS