Welcome to the Cactus Patch Trail at Tonto National Monument! Cacti are a common, but fascinating part of the Sonoran Desert. These succulent or fleshy, water conserving plants are friend or foe. The Salado collected parts of these plants for food and materials. Birds, insects and mammals continue to rely on the cactus for food and shelter. On the less helpful side, unfortunate hikers and animals also collect parts of the cactus -- the spiny parts.
Not all spiny plants are cacti. Cacti are identified by the spines clustered in areoles on fleshy usually leafless stems. In some cacti, these small pits or cavities are scattered on pads and joints. In others, they follow the length of the rib in an orderly manner. Flower characteristics further identify members of the cactus family. Two of the plants on the cactus patch trail are not cacti. Can you figure out which two?
Within the space of a quarter-mile, the Cactus Patch Trail travels through several ecosystems. The thicker vegetation of the wash area thins on nearby open hillsides. Supported by a year-round spring, the green vegetation of the Upper Cliff Dwelling Trails' riparian area is seen. Beneath the shade and protection of some plants, small environments exist for the new growth of cacti or other tender plants. They also provide habitat for many smaller animals. The Sonoran Desert is filled with hidden ecosystems. Sheltered close to a rock, near a year round spring, and in other places where water collects or travels through, plants and animals exist. In the desert, all living things must find ways to conserve water and adapt to the harsh environment. Existence is marginal, and each plant and animal must find the conditions under which it can best compete for the limited resources. Man also competes. The Salados' successful occupation of the Salt River Valley depended on their ingenuity in discovering practical uses for every fruit, bean, stalk and fiber in the desert.
Looking at the two pictures of thorns, can you figure which is the catclaw acacia (click one of the images to see if you're right)? The "claws" of this plant are not very well liked. Wait-a-minute bush and tearblanket are two other common names associated with the catclaw.
Living at elevations from sea level to 5000 feet, catclaw acacia trees often form thorny thickets along washes and streams. Deciduous, this large shrub or small tree can reach heights of 20 feet and ages to 130 years old. The scaly gray to brown trunks may be as thick as one foot in diameter. The branch and trunk woods were used by the Salado for firewood and tools. Each spring new leaflets return. The small leaflet size prevents too much moisture loss during photosynthesis. Even in full canopy, the leaflets are not dense enough to block the view through the branches. Animals browse the leaves at times of low forage. Blooming heaviest in April and May, flowers continue to appear into October. The yellow, puffy flowers attract many different insects and are an important source of nectar for bees. Part of the legume family, the flowers further categorize the plant into the mimosa subfamily. In June, pods begin ripening. The Salado ground the pods, possibly to make a mush or cake. Once outside the pod, the wax coating of the seeds delays germination for several years. Just one more important resource used by the Salado.
Sometimes they look like lonely sentinels guarding over the surrounding vegetation and other times they gather in groups of cactus people with features as different from each other as every human being. The saguaro (sah WAH ro) is a species of cactus living only in the Sonoran Desert, mainly in southern Arizona and the state of Sonora, Mexico. They live from sea level to about 4,000 feet in elevation, preferring well drained soils of plains, hills and slopes. Tonto National Monument is near the northeastern edge of saguaro habitat as their sensitivity to frost and freezing limits contains their range. In this rugged Arizona Upland region, saguaros are most common on the warmer east and south facing slopes, growing to an average of 50 feet in height. Growth is a slow process for the saguaro – reaching about a half-inch the first year, about one foot the first fifteen years, about ten feet in 40 to 50 years and from twelve to twenty feet in 75-100 years. As the saguaro grows, it is able to absorb more moisture to sustain its growth for longer periods, thus increasing the growth rate. Saguaros take between 50 and 100 years to grow their first arm and some never grow arms. The number of arms does not relate to age, but to the soils and the amount of rainfall. In dryer areas, saguaros are smaller and have fewer arms. Occasionally, a cactus develops an abnormal growth of unknown origin, possibly damage of some type to the growing tip. The growing tip enlarges and flattens, creating a giant fan-shaped crest known as cristate, fasciated, or just plain crested. Crested saguaros are more obvious than other crested cactus due to their height.
Spines on the outer ribs of the saguaro provide shade for the trunk and protection from animals. Spines grow out of areoles in groups of 15-30 and up to three inches long with the longest one pointing down. On young plants the spines are sturdy. As saguaros grow, spines are strong below about eight feet on the trunk and are bristly above. As it ages, the spines change in color from white to black to gray. They are not replaced if broken off and older saguaros even shed their spines on the lower trunk and develop a rough gray bark.
It’s easy to see why the saguaro blossom was chosen as Arizona’s State Flower. Once the saguaro reaches the height of about eight feet, it begins its first flowering. How long it takes the saguaro to reach this height depends upon available moisture; so, first blooming may take place from about 40-75 years old. May-June, beautiful waxy white flowers with yellowish centers grow near the end of the arms or the main trunk. The three inch flowers open at night and remain through part of the next day. Within a month of blooming, an egg-shaped fruit develops and ripens. Green on the outside and juicy red on the inside, the fruit provides food for animals and humans alike. Though a mature saguaro produces as many as 100 fruits in a year, each with about 2000 tiny black seeds, few develop and live to the ripe old age of 150 years or more.
Much is known of this well-studied cactus and its adaptations for survival in an arid environment, most revolving around moisture - acquisition, utilization and loss prevention. Shallow roots spread out as far as the saguaro is tall. During the driest times, outlying roots die off, growing again within a day after a storm. These extensive root systems allow a mature saguaro to soak up as much as 200 gallons of water during a rainstorm. As the water is absorbed, the pleat or accordion structure of ribs and indents allows expansion to accommodate all of the moisture and the saguaro stem and arms are more rounded and fat. As the stored moisture is used during dry times, the pleat indents deepen and the saguaro becomes thinner. Since the saguaro is leafless, photosynthesis takes place in the stem. Small valved pores or stomates in the waterproofed surface of the saguaro close during the day to seal against moisture loss and open at night for the intake of carbon dioxide and output of oxygen. The carbon dioxide is then stored for daytime photosynthesis. Through this slower process, very little moisture is lost, but the cactus also grows much slower. Stored moisture allows the saguaro to bloom and fruit even in dry years. In wet years, more flowers bloom and more fruits develop, providing moisture laden food for many animals in the dry time before the summer storms begin.
Not only was this plant native to the area, but the Salado cultivated it in their fields. Slow growing and living at higher elevations on dry, rocky slopes, not enough agave grew without cultivation to supply Salado needs. The whole plant was used. Split flower stalks were used as slats for roofing and as hearth boards for fire making. A leaf's outside skin and inside pulp were eliminated to reveal the fibers within. The sharp point at the leaf end became the needle for the attached fiber thread. Roasted as a whole, the base of the leaf rosette was eaten like an artichoke. The cooked leaf pulp was shaped into cakes. Providing food, fiber, rope, medicine and drinks, the agave was one of the more important plants available to the Salado.
Though succulent and spiny like cacti, agave does not have the same structures to include it in the cacti family. The agave's hooked spines line the leaf margins instead of growing out of areoles. Most cacti do not have leaves. The agave's grayish-green and fleshy leaves grow from the center of the circular leaf cluster or rosette. So tightly bound together as they begin their growth, the new leaves impress their shape and spines on each other before spreading out to join the other leaves. As the agave reaches its maturity, between ten and thirty years old, a flower stalk shoots up from the center of the plant. The plant uses all its energy, stored as sugar and starch, to create the tall stalk and flowers. Blooming June to August, reddish-orange buds turn yellow as they open facing upward on flat clusters - islands in the sky. Pollinated by insects and hummingbirds, the flowers produce a large amount of seeds. Most agaves die after this one chance at regeneration. Leaving nothing to chance, new plants, already formed on the root system, begin to take over.
The agave is well adapted to its arid environment. Since the roots do not extend beyond the leaf rosette, each leaf's spatula shape channels rainwater to the base of the plant. The metabolism slows, but does not stop during droughts or dry season. Finer water absorbing roots are shed to save energy. Not being totally dormant, the agave quickly takes advantage of sudden storms and forms new water absorbing roots within five hours after the first measurable moisture. The moisture is stored to draw on during the next dry time, always preparing for the once in a lifetime flowering.
Two varieties of pincushion cacti have been identified within the park. Arizona fishhook and green-flowered fishhook are their common names. Growing in dry, gravelly areas in elevations to 4,500 feet (3,000 - 8,000 feet for the green-flowered fishhook), this small cactus is easily missed. It doesn't tolerate full sun, so hides under the debris of teddy bear cholla, leaves of bursage, or in other protected areas. With no more than six inches in height, the nurse plants easily conceal the pincushion's single stem or stem clusters. Dense white, straight spines, growing out of closely spaced areoles or cavities, veil the green skin. Instead of ribs, the areoles arise from the tips of long tubercles or knobs that are arranged in two spirals. In addition to each areole's straight spines, one to three hooked and dark colored spines grow, standing out from the stem and other spines.
Dormant during the dry season, the pincushion is an indicator of the arrival of monsoon rains. Buds created during previous summer growing season lie dormant until the first monsoon rain. Five days later, buds burst forth into small white to pink flowers ringing near the cactus tip. A second and sometimes a third flowering occur after the next rains. Each flower lasts about a week. Next, the fleshy fruits develop. Though edible, it would have taken the Salado much effort to collect substantial amounts of the small fruit. Much easier eating for birds and small mammals.
Another cacti seen in more places than just the desert is the prickly pear. Living for 30 or more years, various species range from southern Canada to southern South America in arid deserts, tropical woodlands and high mountains. Three varieties of prickly pear live at Tonto. Englemann's, black-spined, and pancake are their common names.
Stems or pads of the prickly pear grow in distinctly jointed segments. These joints continue to grow until the dry season begins. New growth begins with a new pad. Whether or not they have spines, they have glochids. Glochids are small to minute barbed spines that are very sharp and brittle. They are easily detached by anything that touches it. Blooming in May, each yellow flower lasts only a single day, some aging to an orange color. Fruit, called tuna in Spanish, ripen to purple and red in July and August. In addition to young pads, the Salado harvested the fruit for food. The juice squeezed from the pads has been used for hundreds of years to strengthen adobe mortar. Did the Salado know this secret?
Many animals eat the fruit and pads, and some use the spreading cacti as shelter from predators. The cochineal bug, which feeds on prickly pear pads, played an important role in Spanish conquest history. Learning of its use by native people to make a crimson dye, the Spanish made money by secretly exporting this rare dye color to sell in Europe.
Pronounced "choya," this tree-type cholla is also known as the jumping cactus. Ranging from south central Arizona into most of Sonora, Mexico, these cacti prefer the finer soils of the valleys and lower bajadas. With their many trunks and branches, these cacti can reach heights of eight feet or more. In good soils the height may pass 12 feet and be as wide. New growth occurs in two ways. A segment of dense spines grows until the start of the dry season. New growth is begun in the new season with the addition of a new segment. A second growth occurs to extend the lengths of the chains each year. Small pink flowers develop as new joints on the previous year's fruits. Flowers open in the afternoons during the summer months of May to August. By the next morning, fruit begins to form from the dried flowers adding to the older branches and hanging fruit chains. From time to time, chains measure up to two feet long. The fruit and sometimes the stem were used for food by native people, even more so in times of limited food. This cactus has adapted to the limited fertility of its seeds by sprouting roots from the dropped stem segments or the fleshy rinds of the fruit left by the deer and javelina. Falling not far from the original plant, dense cholla colonies are formed. A favorite nesting site of the cactus wrens and curved bill thrashers, the spines deter many a predator.
Many talk about the cacti jumping, but it is actually a myth. As the barbs of the spines enter the clothes or skin, they grab stronger than the segments attach to each other. As the segment snaps off the cactus and into the person or animal, the cactus looks like its jumping. This desert plant is definitely not a favorite of hikers.
Out of water in the desert? Water from desert cacti is a myth, but if you have the right tools and energy to cut into the stem, you could get to the pulp of the Arizona barrel cactus. Of course, if you had all that, you probably were prepared to bring enough water. Be careful, most cacti pulp is inedible, even toxic. Even the Arizona barrel's pulp can create side effects, worsening your problems. Even more serious, it is illegal to damage or dig up the cacti.
Lost your way? Barrel cactus may help you out, but only the compass barrels, another common name for both the Arizona and California barrels. These cacti tend to lean to the southwest, sometimes to the point of falling over. No one is sure why they lean, but feel it has something to do with the heat of the sun affecting growth patterns.
Two varieties of barrel cactus are identified at Tonto National Monument. They are similar in many ways. Both are usually unbranched unless the growing tip of the cacti is damaged. The pleated stems allow expansion for sudden storms and shrinkage during dry times. Located on the outer rib of the pleats, the longer central spine sticks out from the spine cavity or areole and is ringed by other small spines. The barrels are usually globe-shaped, becoming more columnar as they grow to heights of ten feet or less. Rodents, birds, mule deer, bighorn sheep and javelina eat fruits and seeds. Cactus beetles, jackrabbits, packrats and javelina, eat the plant itself. It is estimated they live for more than a hundred years. There the similarities end.
Sometimes confused for young saguaro, the California barrel grows from sandy alluvial plains to steep rocky slopes. Their red, yellow, or brown central spines are flat and curved at the tips, but not hooked. They are dense enough to hide the stem beneath. The short, funnel-shaped yellow flowers appear in March and April among the dense spines of the cacti stem tips.
Arizona barrel, Candy barrel or fishhook barrel cacti are a few of the common names for the other monument cactus. It prefers the gravelly bajadas below the steep hills. Its long, wide and flat central spine is crosshatched with little ridges and curves downward at the end. Red in color, the Salado created rings from the spines. Smaller white to light yellow bristly spines circle the central spine partially hiding the skin of the barrel. Orange, red, or yellow flowers appear July to September. The bright yellow fruit may remain on the cacti for more than a year.
Growing in elevations to 5,000 feet in California, Nevada and Arizona, the hedgehog tends to blend in with its background. It is found living in sandy flats, rocky flats and hillsides. The stems, in clusters of five to fifteen, only grow to about a foot tall and three inches in diameter. For such a small cactus, it carries large spines. Growing along each of the ribs, the central spines are about two inches long and are circled by one-inch spines. White, yellow, pink, red, or gray -- the varied color dense spines shield the stems from sunburn and animals. Two varieties of Hedgehog are shown - robust and strawberry.
Bigger than a pincushion cactus, but smaller than a barrel cactus, a hedgehog cactus is sometimes missed until its beautiful flowers shout, "Here I am!" First of the cacti to bloom each year, hedgehogs lead the way into spring. The blooms, in varying shades of magenta, appear March to May. The flowers stay open for several days. Later, green spiny fruit develops, turning red as it ripens. As the fruit matures, the spines become loose and can be brushed off. Both humans and animals enjoy the edible fruit with its sugary juice. It's easy to see why one hedgehog is named "strawberry".
The desert Christmas cholla is another of the various cholla found in the desert. It is the most prevalent of all the cholla varieties, ranging from Arizona to Oklahoma, south to Texas and Mexico. Its habitats are washes, flat areas and slopes at elevations of 1,000 - 4,000 feet. In open areas, this cholla's height can reach three feet.
It prefers the protection of desert trees, growing like a vine to much taller heights. Hidden among trees or other plants, a hiker or an animal can be unpleasantly surprised. Branched and slender, the dark green joints are up to one half inch in diameter with easily detached, short lateral joints growing off the main joints. The smooth joints are usually protected by one central spine of about two inches in length. The gray color of the spines is revealed when the tan sheaths drop off in the fall. Small white bristles cover the areoles or spine cavities.
Flowers of green to yellow bloom May to June, opening in mid afternoon only to close again by dark. Small green fruits develop and, as appropriate for a Christmas cholla, ripen to a bright red during December. The fruits remain through February and are covered with itchy glochids, small barbed spines that are difficult to remove because they are so small. As with most cacti, nothing stops the various fruit consumers. Birds and rodents dine after being attracted by its bright color and some native people cook the fruit into jam.
Named for the forked branches resembling deer antlers, buckhorn cholla might easily have been named adaptable cholla. Throughout its range of southern California to eastern Arizona, a buckhorn's characteristics vary, with almost every mountain range and valley displaying a different-looking population. Is this a process of evolving into a new species or just the ability of adapting to the needs and conditions of each different environment?
Living on rocky and sandy slopes to 4000 feet in elevation, a buckhorn's branching stems spread the plant to ten feet across. With an average height of three feet, buckhorns appear bushy with many thin branches rising from the ground. With a short trunk and greater heights to thirteen feet tall, it appears tree-like. The stems, light to dark green, grow six to ten inches long. As with many cacti, the stems are tinged with red or purple during drought or cold weather, responding to stress. Eight to twenty spines grow out of the stems' easily visible knobs or tubercles. These spines, about ¾ to 1½ inches long, are dark brown and covered with thin straw-colored sheaths. Flowers begin opening in April and vary in color. Flowers of yellow, red, orange, pink, purple, greenish or brownish are seen, many times within the same local population. Fruit of tan to brown appears soon afterward. At maturity, the fruit has many tubercles and is covered with long, barbed spines. The tip of the dry fruit is broad and slightly depressed. The fruit falls from the plant after several months. Buckhorns are not a preferred nesting area for birds because of the openness of the branched stems and the fewer number of spines. Many native people, however, prefer to eat the buckhorn's flower buds to the flower buds of other chollas.