Not all of the spiny desert flora are imposing. The pincushion cactus, as tiny and round as its name implies, huddles next to boulders or crouches among grasses and is often difficult to find before its flowers shyly open to the world.

This cactus is also referred to as the Arizona fishhook, because the plant sports long black central spines that are curved like a fishhook.

The pincushion cactus is characterized by many long white spines. These spines provide a dense covering, which may protect the cactus from the heat of the desert.

The pincushion cactus is found from southern Arizona to west Texas. These cactus grow in dry gravely areas, usually in the shade under trees and shrubs. Young plants form a cluster around the parent plant when they begin to grow. Pincushion cactus can survive at elevations from 1000 to 5500 feet. Ten species of pincushion cactus are found in Arizona.

Flowers bloom between April and August, usually a few days after a rain. They are deep to light pink and have a stripe down the middle of the petal. These flowers form a crown on top of the stem and last for several days. Fruits appear after this and are approximately one inch long. They are bright red and club shaped.

It is not unusual for the unwary hiker to find himself drafted into the unwelcome position of transporting the chainfruit cholla's spiney joints to new growth locations. The chainfruit is often called the "jumping cholla" because of the ability of its joints to easily detach from the main plant and cling to clothing, fur, or skin. This cholla is often considered the most "stickery" of all cactus, for good reason; attempting to remove those joints can be a painful job! (Try using a comb).

After the cholla's joints fall onto the soil, they may take root, thus providing an efficient means of asexual reproduction. In addition, the chainfruit is the only cholla which produces sterile fruit. These grow directly out of one another in long chains until heavy enough to break off the main plant, fall to the ground and take root.

At least six different species of cholla can be found in the Tucson area. The cholla's scientific name, "Opuntia," means "jointed plant."

The cholla's spines are a mixture of long, silvery-yellow spikes, which enable it to stick to things and be carried, and tiny, yellow and red barbed glochids. The cholla is a common nesting place for some desert birds, especially cactus wrens, which find protection among its spine clusters. It is also an important resource for packrats. They often construct tunnels leading through cholla thickets, and add detached cholla joints to the walls of their nests to provide added protection from predators. In addition, they may use the cholla as a water source.

The chainfruit cholla produces peach, pink, or red blossoms in spring and early summer and may bloom through August. Its interactions with other, less numerous cholla species on the grounds of Biosphere 2 Center contribute to a hybrid swarm of cholla varieties.

Native to Arizona, the velvet mesquite produces masses of tiny yellow spring and late summer (post-monsoon) flowers, which are pollinated by a wide range of insects, including 60 species of native bees. Most of the flowers will never mature into fruit, serving only to attract the pollinators, but some become edible pods. A single tree can produce 35 pounds of pods in a year. The Tohono O'odham Indians of the area used the pods, which are produced even in drought, to make flour. In this process, the seeds are winnowed from the sweet pulp.

The mesquite's most impressive adaptation to its dry habitat is its deep root system, which may extend to a depth of 60 feet and supply the tree with adequate water even during very dry periods.

The palo verde tree's distinguishing feature, its bright green bark,  has a very practical purpose in the desert. The palo verde carries out photosynthesis in the bark itself, so it does not require the large leaves that many wet-climate plants develop. Thus, the tree obtains the energy it requires while losing only a minimal amount of water by evaporation from its leaves.

A second mechanism for surviving the desert heat is the light color of the tree. The tree is able to reflect excess energy of the sun, rather than absorbing it. This phenomenon, known as "high albedo," lowers the internal temperature of the palo verde.

In the spring, the palo verde develops bright yellow flowers with red spots on the petals. While the seeds which replace these flowers are soft and immature, they are edible and delicious! The palo verde, which reaches its upper limits on the Biosphere 2 Center site, is the official state tree of Arizona.

There are places in this area where prickly pears grow so thickly it is difficult to tell where one plant ends and the next begins. The pads, which look like beaver tails growing out of one another, spread outward in low, thick gardens of needles, which erupt into beauty when they produce large yellow flowers in late spring.

The prickly pear's hardiness enables it to live in a surprisingly large range of conditions. Different species can withstand heat of over 100 degrees F and cold as low as -40 degrees F, so they can live from North Dakota to Texas and Arizona and south into Mexico. They are even found in tropical Hawaii. There are over 300 species.

Prickly pear fruits, or "tunas," are beet-colored and shaped like a large olive. They are used for many types of food including jam and salsa. The young pads can also be eaten as "nopales" once they are de-spined and cooked.

Prickly pear cactus also contains a gooey juice that is a very soothing skin lotion for minor rashes, sunburn and windburn. Snakebites and insect bites are also treated with a poultice made from de-spined prickly pear.

In some areas, limiting factors for the prickly pear are loss of habitat due to natural factors, such as erosion, and human factors, such as logging and agriculture. Prickly pear is often favored by excessive grazing, due to its incredible hardiness and ability to colonize places where grass has disappeared.

The first images that come to mind when the word "mistletoe" is mentioned are usually of warm fireplaces, Christmas trees, kisses, and snow. It may surprise you to learn that the desert has its own variety of mistletoe, although a "white Christmas" is a rare event here.

Visible as dense green or red-branched clumps in the branches of mesquite or palo verde trees, the parasitic mistletoe plant roots itself directly into the branches of its host tree and "steals" the water and nutrients which the tree takes from the soil to feed its own branches.

If unhindered, the mistletoe can eventually kill the host tree. Before its life cycle is completed, it must ensure that its offspring are transported to different trees. Birds eat the mistletoe berries and disperse their seeds. These berries are filled with a very sticky juice, which anchors the seeds to the tree bark upon which they are deposited. Soon after deposition, the seeds put out thread-like roots which penetrate the bark of the host tree and thicken, enabling the mistletoe to reach the nutrients it requires.

The berries and stems of the mistletoe are poisonous to humans and, if ingested, will cause abdominal pain and digestive tract complications.

When one stands beneath the tall, straight saguaro, considered by many to be the symbol of the Sonoran Desert, its weight and strength become suddenly real. The heavy plant creaks and moves very slightly with the wind.

The Arizona state flower, and the largest cactus in the United States, the saguaro can grow to be 50 feet tall and the stems may be 18 to 24 inches in diameter. When water is absorbed into the outer pulp the cactus expands and may increase its weight more than one ton.

These cactus grow commonly on rocky hillsides and outwash slopes at elevations of 0-1400 m. They are generally more abundant on south-facing slopes than north-facing slopes, because of increased winter sunlight.

White flowers appear from late April to early June. They open in late afternoon and close the next afternoon, never to bloom again. One stem of a saguaro may produce over 100 flowers, which bloom at different times. Pollination of the saguaro occurs mainly at night and in early morning by bees and the whitewing dove.

Fleshy fruits, which are 6 to 10 cm long turn red or purple at maturity and split open revealing many tiny black seeds. Coyotes, peccaries and other animals eat the fruit and disperse the seeds.

Parts of this plant are used by the Tohono O'odham for food and as building material. It is also the home of the gila woodpecker and Gilded Flicker which chisel out small holes in the trunk. Many other animals use these holes when the woodpeckers leave.

Sturdy and long-living, each solitary barrel cactus becomes as familiar as a favorite rock to desert dwellers.

The columnar barrel cactus ranges from 2 to 10 feet in height and 18 to 33 inches in diameter. This species is found primarily in desert grassland and desert shrub areas of the northern Sonoran and northwestern Chihuahuan deserts.

These plants live from 50 to 130 years. They are extremely drought resistant and heat tolerant. The barrel cactus flowers in summer. The cup shaped flowers are red, orange or yellow and approximately 5 cm in diameter. These last for only four days. Yellow fruit may stay on the plant for up to a year.

In certain parts of its range the barrel cactus is not reproducing well. This may be because of grazing or climatic change. Barrel cactus are limited by the fact that they are frost sensitive.

Cactus candy is occasionally made by boiling the succulent tissue and adding sugar and flavoring. The cactus was used by the Seri Indians as a water source. They also cooked the flowers for food, made gruel from ground seeds, and used hollowed out plants as honey containers.

To those who live in this desert, the ocotillo announces the beginning of spring with its late February to early April transformation from rough brown stalks to slender, leaf-covered wands tipped with bundles of bright orange-red flowers.

A shrub ranging from 2 to 10 m in height, the ocotillo may look like a type of cactus, but it is actually related more closely to the primrose and olive. They are commonly found on rocky outwash slopes and plains. They prefer granite at lower elevations and limestone at higher levels. They reach maturity at 60 to 100 years and live to be 150 to 200 years old. The blooming of the ocotillo seems to correspond with hummingbird migrations, while leafing may occur multiple times during the year.

All parts of the ocotillo have been used throughout history. The stems are used to support thatched roofs and as frameworks for brush houses by the Seri Indians. The Cahuilla Indians eat the flowers and capsules. The Apache Indians bathe in ground-up roots to relieve fatigue and also apply powdered root to painful swellings.

Sources:

Bowers, Janice Emily. Shrubs and Trees of the Southwest Deserts. Tucson, AZ: Southwest Parks and Monument Association. 1993.

Cacti. Internet address: amng.orga058/pnCusMre.html. March 24, 1997.

Cercidium floridum. Internet address: http://phylogeny.arizona.edu/classes/lar335/unit4/cercflor.htm. Research conducted on March 24, 1997.

Cholla. Internet address: http://www.netcracker.com/netc/sunoversand/ cholla.html. Research conducted on March 24, 1997.

Desert Plants. Internet address: www.desertusa.com/nov96/du.ocotillo.html. March 10, 1997.

Desert Plants: Cacti. Internet address: ifs.plants.ox.ac.uk/fao/tropeed/data/r422.htm. March 8, 1997. Epple, Anne. A Field Guide to the Plants of Arizona. Helena: Falcon, 1995.

Fischer, Pierre C. 70 Common Cacti of the Southwest . Tucson: SW Parks and Monuments Assoc., 1989.

Forest Pathology: Parasitic Plants, "Root Parasites." Internet address: http://www.pharm.arizona.edu/centers/poison_center/plants/mistletoe.html. Research conducted on March 24, 1997.

Grieve, M. Botanical.com: A Modern Herbal, "Mistletoe." Internet address: http://www.botanical.com/botanical/mgmh/m/mistle40.html. Research conducted on March 24, 1997.

Mistletoe. Internet address: http://www.pharm.arizona.edu/centers/poison_center/plants/mistletoe.html. Research conducted on March 24, 1997.

Ocotillo. Internet address: phylogeny.arizona.edu/classes/lar335/unit11/fouquple.htm. March 12, 1997.

Pincushion Cactus. Internet address: members.gnn.com/iamklaus/botany.htm. March 24, 1997.

Prickly Pears in General. Internet address: amsertdam.park.org:8888/Pavilions/Food and Markets/Herbs/qr_424.htm.March 17, 1997.

Prickly Pear. Internet address: pathfinder.com/@@Qon7AW7WAvJX9/vg/TimeLife/CG/Books/EO8/Htm/ EO8D88X.html. March 12, 1997.

Prosopis velutina. Internet address: http://phylogeny.arizona.edu/classes/lar335/unit4/prosvelu.htm. Research conducted on March 24, 1997.

Saguaro. Internet address: www.desertusa.com/july96/du_saguaro.html. March 10, 1997.

Saguaro cactus. Internet address. www.fs.fed.us/database/feis/plants/Cactus/CARGIG/. March 10, 1997.

Saguaro Flowers. Internet address: floraww.eeb.ucom.edu/acc_num\852363.htm. March 10, 1997.

The Ocotillo. Internet address: www.fs.fed.us/database/feis/plants/SHRUB/FOUSPL/. March 10, 1997

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Turner, Raymond M., Janice E. Bowers, and Tony L. Burgess. Sonoran Desert Plants: An Ecological Atlas. Tucson, AZ: The University of Arizona Press, 1995.