Bizarre blooms of Baja: with a variety of habitats and weather conditions, this pristine peninsula harbors a range of unique plants.

Mark Dimmitt was puzzled. The creeping devil cacti that he and his colleagues sought on Mexico's Baja California Peninsula were not where memories from previous trips told him to look. Not only could he not fred the mysterious cacti, but the Pacific Ocean was not where his maps and the car's odometer said it should be. After some head scratching, though, Dimmitt, director of natural history at the Arizona-Sonora Desert Museum in Tucson, plowed ahead over a few more tall sand dunes. Soon he found himself surrounded by hundreds of the alien-looking creeping devils, all pointing in different directions.

There are perhaps few plants in the world stranger than the creeping devil cactus. Known on Baja as chirinola or casa de ratas (rat house), the creeping devil reaches about five to ten feet in length. It has long, very sharp spines, large white flowers that bloom at night and scarlet-colored fruit. The cactus is found in only place--on sandy softs near the Pacific coast of the Magdalena Plains in southern Baja.

But none of those characteristics are what make the creeping devil strange. Rather, it is the way the cactus grows. Unlike most plants that grow upright, the creeping devil lies flat on the ground, its front end tipped up. Roots descend wherever the cactus touches the soil. Even stranger, it continues growing from its front end while the back dies and disintegrates. Thus, anyone who revisits a patch of creeping devils after several years' absence might think the plants had moved or crept from one place to another.

The creeping devil is just one of many Baja plants that look weird, have strange-sounding names, or unusual characteristics. These include the boojum and elephant trees, a bursage with fruits more like a cactus, and such real cacti as the sour pitahaya and cardon. Moreover, botanists are still finding strange new species on Baja and strange new things about plants that seemed already well known.

"Baja plants are weird, not only in their looks but in many other aspects," says Jon Rebman, curator of botany at the San Diego

Natural History Museum. Dimmitt agrees. He calls the creeping devil "bizarre," adding: "In Baja, where there are so many strangelooking plants, such thoughts are mundane."

Not only does Baja have a lot of unusual plants, but a surprising diversity, too. With more than four thousand taxa or related groups of plants, more than most U.S. states, the peninsula is the most diverse part of the Sonoran Desert, says Rebman. Thirty percent of all Baja plants grow only there. Of the 130 taxa of cacti growing on Baja, 70 percent are found nowhere else.

Scientists are not quite sure why Baja has such a variety and so many unusual plants, but they cite several factors. One is the location, sheer size, and shape of the place. Located in northwestern Mexico, it has often been called "Baja incognito," "the forgotten peninsula," and "almost an island." It is separated from the Mexican mainland by the Gulf of California (also called the Sea of Cortes). The long, thin peninsula stretches more than eight hundred miles from the U.S.-Mexican border at Tijuana to the tip at Cabo San Lucas, but is only 50 to 150 miles wide. Baja is nearly twice as long as Florida, the longest peninsula in the United States. Only the Malay Peninsula in Asia is longer.

Because of its length, Baja encompasses a tremendous variety of habitats. They range from Pacific coastal chaparral in the northwest to thick thorn scrub, palm trees, and a tropical dry forest in the subtropical southern cape. In between are pine, aspen, and oak-covered mountains, with one, the Sierra San Pedro Martir, rising more than ten thousand feet in elevation. Bays lower Pacific and gulf coasts feature mangrove wetlands and nutrient-rich blue lagoons that attract numerous whales and other marine mammals. Rocky islands dot the gulfs offshore regions.

But the largest and most biologically interesting areas of Baja are the deserts that dominate most of the peninsula. Most of Baja's unusual plants and much of its diversity are found in the desert's coastal sands, inland plains, dry washes, protected canyons, huge boulder fields, and rugged mountainsides. On the Pacific coast, the desert begins at El Rosario and reaches south almost to the tip of the peninsula. On the gulf side, it goes from Mexicali on the U.S.-Mexican border south almost to La Paz, the state capital of Baja California Sur. Often referred to separately as the Vizcaino, Magdalena, and San Felipe deserts, all are part of the larger Sonoran Desert. The latter stretches from northern Sinaloa through most of Sonora on the Mexican mainland to Phoenix and Kingman, Arizona, and into southeastern California.

Baja's diverse weather patterns also contribute to the peninsula's unusual flora. Rainfall averages range from twenty-eight inches in the Sierra San Pedro Martir, where winter snow can sometimes reach nine feet deep, to two inches in parts of the Vizcamo. But those numbers can be deceiving. Desert rains often fall in the form of occasional storms called chubascos that can drench the peninsula with six or more inches of ram at one time. Afterwards, no appreciable ram might fall for two or three years. Further, the northern portions of Baja get mostly winter rains, while the south has mainly summer ones. Some of the strange forms Baja plants take are adaptations to the peninsula's different climates, seasonal rains, and lack of predictable rainfall.

Moreover, the Pacific Ocean's California Current carries cool water from farther north, creating frequent coastal fogs, especially from February into June. The fogs often drift inland, almost to the gulf coast. They condense on cool surfaces, providing additional water for Baja plants. The ocean also often generates strong winds that shape sand dunes and influence how and where some plants can grow.

Finally, Baja's geologic history has influenced its plants. Once part of the Mexican mainland, tectonic forces deep below the earth's surface caused Baja to break away some five to twelve million years ago. Baja slowly drifted northward as an isolated island until it bumped into California. By then, the peninsula harbored plants that had evolved separately from their relatives on the Mexican mainland. Other plants in California such as manzanita, a shrub with smooth red wood, migrated south into Baja.

Further, Baja's plant communities look different today than they did eons ago, says Thomas Van Devender, a senior research scientist at the Arizona-Sonora Desert Museum. Van Devender studies packrat middens, the hardened remains of where generation after generation of the rodents urinated in the same spot, often for thousands of years. The sticky middens collect leaves, seeds, pollen, bones, and whatever else blows or falls into them. They can be dated and analyzed to determine what plants and animals lived in Baja in bygone eras.

By studying packrat middens near Catavina, Van Devender found that Baja's deserts are relatively recent. The Vizcaino region, now one of the Sonoran Desert's driest, combined a pinon juniper and oak woodland with chaparral about twenty thousand to forty thousand years ago. Chaparral came to dominate the Vizcaino as the area became warmer and drier when the glaciers retreated farther north. That gave way to the current desert thorn scrub only within the last ten thousand years. "Those changes have helped make Baja one of the most fascinating places on earth," Van Devender says.

True, but with some equally interesting qualifications. For one, not all the peninsula's strange plants grow only on Baja. Many appear elsewhere in the Sonoran Desert and beyond in Mexico and the U.S. Southwest. But, they often take a more normal appearance outside Baja. Others may have more normal-looking relatives elsewhere. And Baja has no exclusive claim to the world's strange plants. Many, like the African baobab tree, grow in other dry environs.

And what to outsiders may seem strange, exotic, or weird appears commonplace to Baja residents and students of its plant life. "To me, [Baja's strange plants] are not that unusual," says Richard Felger, a research botanist and head of the Dry Lands Institute in Tucson. "What's strange are all those green trees growing where you live. The people in Baja do not think their plants are strange." Still, Felger and most other botanists admit, the plants found outside Baja are more like most plants growing around the world than are Baja's.

Take the creeping devil cactus. While its horizontal growth form is unusual, it is not unique. Some South American cacti, most notably one known to science as Echinopsis thelegonus in Peru, start upright, but later fail over and grow along the ground. Rebman thinks that may be how creeping devils deal with the strong winds that blow across Baja from the Pacific. Interestingly, the creeping devil typically adds two to three feet of new growth a year on Baja, but only a couple of inches at botanical gardens in Tucson and Phoenix. The cactus is apparently adapted to the Magdalena's fog-driven cool, moist desert climate, not Arizona's hot, dry one.

Perhaps even stranger than the creeping devil is a tree called the boojum. Known locally as cirio (tapered candle), the boojum was named by English explorer Godfrey Sykes in 1922 after the mythical creatures that occupied distant shores in Lewis Carroll's The Hunting of the Snark. "Boojums are what you get when you take a stem from an ocotillo [a common desert shrub with long, thin branches that grow from the ground up], fill it with water, and stick it in the ground," Dimmitt says. They are "surely one of the top ten most bizarre plants in the world." Others think the boojum looks more like an upside-down carrot.

Typically reaching sixty feet or more, the boojum has a thick lower trunk that becomes progressively thinner towards the top. The upper trunks on some older boojums split into two or more stems. Others may double over near their tops, forming a U-shaped arch as they reach back to the ground. But, strangest of all, the boojum lacks large, canopy-forming limbs like most other trees. Instead, it puts out short, pencil-thin branches that gives it an unkempt appearance. Like some other desert plants, the boojura sheds its leaves during dry periods and grows them again after a winter rain.

The boojum grows mostly in central Baja. It prefers well-drained hillsides and plains. In some places, it grows so densely as to form a virtual forest. Unlike the creeping devil, the boojum is also found on the Mexican mainland south of Puerto Libertad along the Sonoran coast. Here, an upwelling of cold water in the Gulf of California creates conditions similar to Baja's cool fogs.

Like the creeping devil, Baja's boojum, while strange, is not unique. Felger points to two closely related boojums in southern Mexico that look more like normal trees than their Baja cousins. He thinks the unusual Baja trees represent an extension of the plant's juvenile form into adulthood. That form allows the boojum to intercept fog sweeping in from the Pacific, causing it to condense on and run down the trunk to the ground, where the boojum's roots can absorb the water. Some other Baja plants similarly take advantage of water vapor in fog.

How tall and old a boojum gets often depends on where it grows. Decades ago, botanist Robert Humphrey of the University of Arizona thought that the boojum, like other desert perennials, grew only a few inches a year but could live hundreds of years. More recent studies indicate it grows faster but has a shorter life, especially those trees close to the Pacific coast, where hurricanes often blow them over, says Robert Webb, a U.S. Geological Survey hydrologist and plant ecologist.

Webb examined a series of photographs collected by Raymond Turner, a retired USGS researcher and saguaro expert. Few of the boojums in 1905 photos of study sites near the Pacific coast were still around in the 1990s. Nor could many of those in photos from the 1950s be found forty years later. Given their relatively short lives, few grew taller than thirty feet. The only places they get taller, Webb says, are in protected inland valleys.

Yet another unusual Baja plant is the elephant tree. Actually, Baja is home to several plants called elephant trees, including ones in two different botanical families. Adding to the confusion, similarlooking trees in Africa in yet other families are also sometimes called elephant trees. Whatever their scientific classification. Baja's elephant trees are strange. Typically reaching no more than twenty-five feet, elephant trees have thick lower trunks that store water. That enables the plants to survive the peninsula's long droughts. "They look like someone stuck a hose in them," Dimmitt says. Elsewhere. in places with more rain than the Baja deserts, related species look more like normal trees.

The Sonoran Desert's most common elephant tree is the torote (big bull) or copal. Known to science as Bursera microphyllo, torote is recognized by its aromatic leaves and reddish-brown branches. It is related to trees that produce frankincense and myrrh. Another elephant tree, called copalquin or palo blanco in Mexico (Pachycormus discolor), is confined to Baja. Copalquin can be distinguished from torote, which to add to the strangeness of Baja plants is sometimes also referred to as copalquin, because of its white bark. Both have short, stout trunks, many crooked branches, and thick, fleshy bark that give them a grotesquely twisted appearance.

Unlike the boojum, which often grows in sandy soils near the Pacific coast, elephant trees are usually found in bedrock. That gives them better anchorage so that few are knocked down by storms. "We never saw an elephant tree blown over," Webb says. "It is hard to find dead ones even in repeat photos." In fact, Ray Turner's fifty-year-old photos show the same elephant trees today in the same places as then. The photos also show only minimal growth over that half century.

Elephant trees, boojums, and creeping devils are not the only strange Baja plants. Take the cardon, the tallest North American cactus, which looks like and is often confused with its more widespread and better known relative, the saguaro. The cardon is found throughout Baja's deserts, on most Gulf of California islands, and along the Sonoran coast, sometimes reaching sixty feet or taller. It can be distinguished from the saguaro by its armlike branches that grow straight upwards, giving it a more massive appearance. Saguaro branches are more likely to curve out and up, candelabra style. No saguaros grow naturally on Baja.

If the cardon's appearance is rather normal, its sexuality is not. Recent research by Theodore Fleming of the University of Miami has shown that the cardon has not one, two, or even three sexes, but four. In addition to male, female, and bisexual individuals, some cardons are neuters. Neuters produce sterile flowers and no seeds. So far, the cardon is the only known plant with neuters.

But the cardon is not the only Baja cactus with strange sexuality. Some cholla cacti have two sexes--females and bisexuals. So do some Baja pincushions. And a hedgehog cactus on Baja has three. So does the sour pitahaya, a candelabra-shaped cactus that can reach fifteen feet in height. The pitahaya's thick, sprawling branches often form impenetrable thickets. Outside Baja, though, the sour pitahaya has only two sexes.

Finally, one Baja bursage (Ambrosia bryantii) has characteristics that make it seem more like a cactus than a woody shrub. This inconspicuous little bursage produces fruits with long, sharp cactus-like spines. The spines catch on the fur or feathers of passing animals, which unintentionally disperse the seeds. Several species of cholla cacti (collectively known as "jumping chollas") similarly attach themselves to passersby. "None of its relatives are so bizarre," says Van Devender of the Baja bursage.

Until recently, these and other Baja plants were considered well protected by the peninsula's remoteness, forbidding environment, and lack of people. More important, plentiful preserves throughout the peninsula protected Baja's biological diversity. These include the Upper Gulf of California and Colorado River Delta Biosphere Reserve, the fifteen thousand-acre Sierra San Pedro Martir National Park, and the more than six-million-acre Vizcaino Biosphere Reserve.

More recently, new threats to Baja's natural environment and strange plants have arisen. For one, Webb fears that boojums are declining in many areas of Baja due to climate change and the popularity of their interlaced wood for ornamental use. For another, Americans and other foreigners can now use local land trusts to own land in Mexico. On Baja, especially desirable are beachfront properties. One proposal would build five thousand new homes, mostly for Americans, between Loreto and La Paz on the gulf coast.

More serious, the Mexican government is promoting Mar de Cortes, or Sea of Cortes (formerly Escalera Nautica, or Nautical Stairway), an ambitious $2 billion effort to build new roads, airports, resorts, hotels, golf courses, and marinas at or connecting twenty-four sites along Baja's Pacific and gulf coasts. Some would be within the biosphere reserves. The project is designed to increase tourism and create jobs for the many impoverished residents of Baja. But it threatens "one of the most pristine areas left in the world," says Baja native Alonso Aguirre, the Wildlife Trust's director for conservation medicine.

Instead, some Mexican and U.S. groups are advocating Escalera Ecologica, or Ecological Stairway. The alternative proposal calls for more limited development that focuses on low-impact ecotourism at existing and new preserves. "Some development is going to happen," says Wallace Nichols, director of Wildcoast, a U.S. conservation group devoted to preserving natural Baja. "We want development that will work with and not destroy nature."

At least some Mexican officials agree. "Baja is reaching its limits of growth," says Ezequiel Ezcurra, president of the National Institute of Ecology, citing water shortages. "I would rather see more low-impact, environmentally friendly tourism," Ezcurra adds, pointing to financial problems that have kept most Mar de Cortes projects from getting started. "We should improve the marinas for boats, but also preserve Baja's distinct wild and unspoiled environment. That's what attracts people."

Still, for many, Baja remains largely mysterious. That strange encounter with the creeping devil cacti that Mark Dimmitt reported persisted after he had found the plants. Camping out among the sand dunes that night, Dimmitt and his colleagues wondered whether they would awake in the morning and find the creeping devils had grown all over them. "It all seemed very alien," Dimmitt recalls. Only on Baja.

Jeffrey P. Cohn is a past contributor to Americas on science and conservation subjects.