Xoconostles, a type of prickly pear

The color and variety of many cactus flowers could make your irises swoon, no pun intended. Cactus flowers are generally short-lived. They bloom in the desert, and they usually last only a day or two. Ever seen an epiphyllum? The jungle cactus, or orchid cactus, grows extravagant, ostentatious flowers in unbelievably rich colors. There's an epiphyllum collection at the Wild Animal Park in Escondido that'll take your eyes to a new spectrum. Orchids are okay, and roses carry pedigree, but if you ask me, cacti are the floral kings and queens of the plant world. To look at cacti is to see the imagination of evolution dramatically played out in audacious gestures. How did life come up with so many shapes? Cacti grow in buttons, angles, columns, cushions, cylinders, flat pads, pendants, globes, ovals, sprawls, tubers, pyramids, and treelike, shrublike, and rocklike forms.

Cacti grow in buttons, angles, columns, cushions, cylinders, flat pads, pendants, globes, ovals, sprawls, tubers, pyramids, and treelike, shrublike, and rocklike forms.

The names of cacti reveal the attempts to describe their incredible variety — prickly pear, rainbow cactus, crab cactus, barrel cactus, candelabra cactus, rat tail cactus, chain-link cactus. After reading a few dozen of these names, we might visualize gardens full of teddy bears, cucumbers, and mini spaceships.

Among the thousands of varieties of cactus, we find a link to religious images and holidays: the Christmas cactus, Easter cactus, mission cactus, and bishop's cap. Many cactus enthusiasts make wreaths out of cacti and other succulents. In Native American societies, hallucinogenic cacti were used in holiday ceremonies. So, although corn takes Thanksgiving, the pine owns Christmas, and the pumpkin has Halloween, the cactus lands a spine or two in these holidays and more, which might make the cactus the Great Celebrant of the plant world.

Jon Rebman: "Watch out for glochids! They're far worse than regular spines."

For two days, the first weekend of every June, in room 101 of the Casa del Prado in Balboa Park, dozens of vendors, thousands of hobbyists and scientists and the curious, and tens of thousands of very special plants unite.

Prickly pear cactus. The tuna fish and the fruit of the prickly pear cactus, the "tuna fruit," look more than a little alike.

The San Diego Cactus and Succulent Society's annual show and sale, which is free and open to the public, spills out of spacious room 101 -- potted cylinders and stars, planted pendants and pyramids -- and juts and sprawls into the inevitably sunny courtyard, a million spines and barbs and the loyal fans of the family Cactaceae.

Juan Carlos Gomez: "When it comes to us from the Mexican market, it still has its spines, so we have to be careful and wear some kind of gloves."

Photo by Chris Woo

The society meets monthly in the Casa del Prado. When I went to one of these get-togethers recently, I expected to see nine or ten botanists standing around talking about how to revive their sick pet cactus, "Spike." What I witnessed instead was a vibrant scene: 80 or 90 gardeners, horticulturists, collectors, plant photographers, and other enthusiasts milling through a collection of hundreds of thriving cacti with names like night-blooming cereus and red pitaya. There was a slide show about a trip one of the society members had taken to photograph and collect cactus in Argentina. There was passionate conversation, not to mention ample refreshments. And alongside the usual harmless geekiness that attends esoteric seminars and conferences, at the Cactus and Succulent Society meeting there was also that infectious eagerness that radiates from dedicated hobbyists.

Tom Knapik is a past president of the society who teaches math at Patrick Henry High School. He has a master's degree in botany. When I was introduced to Knapik in the Casa del Prado, he was deeply engaged in a conversation using Latin names and technical lingo. Thankfully, Knapik had no trouble toning it down to chat with me.

"Many collectors can tell you the moment they saw a special cactus for the first time," Knapik said, "that moment when it hit them, and they realized that this was something they wanted to grow in the future. For me, the moment was when I was visiting a friend up in Northern California, and his girlfriend was growing succulents in her attic, under a light. And she showed me these plants, and I went, 'Wow!' And that was it. That started it all. And literally my life has been altered in where I live, in the hobbies that I have, in the people that I've met, in the friends that I have, in the vacations I take: it's all been shaped by my interest in these really unique plants."

The plural for "cactus" is either "cacti," "cactuses," or "cactus." (Many of the collectors I talked to prefer "cactus" as the plural for cactus, kind of the way "sheep" is plural for sheep.) "Cactus" itself is a Latinized Greek word, hence the us ending and the fact that an i at the end can make the word plural. It's the same with those other great ancient Greeks and Romans: octopus, hippopotami, alumnus, nuclei, and syllabus. Which means the cactus is like the imperial Roman senator of the plant world.

"I think it's an underappreciated plant," Knapik said, "since we have cactus in our back yards and in our surrounding areas. People kind of take it for granted. This hobby is much bigger in places like Italy and England, probably because they don't have cacti growing in their back yards. The collectors in those countries are really passionate."

Cactus are not indigenous worldwide. They've been spread around the world by collectors, but, with one exception (Rhipsales baccifera), they developed in the Americas only. Many plants in Africa look like cacti but they're not, they're usually euphorbias (common name "spurges"). Cacti are native to 45 states in our country, all but Alaska, Hawaii, Vermont, New Hampshire, and Maine.

Knapik told me, "European collectors have been caught with cactus filling their suitcases, and the plants sell for hundreds of dollars on the market over there. A lot of collectors here focus on buying only seed-grown or propagated plants, instead of collected plants, which is a good ethic to go by."

Then Knapik said, "Many of the top collectors in this area feel, in one sense, like we're preserving things that are sometimes close to extinction in the wild. We can produce seed from species that are extremely rare because of habitat destruction."

Cacti can be relatively pricey — especially if you want some specially bred variety -- but compared to orchids, for example, they're cheap. The most you might pay in San Diego for a rarer cactus would be about $80.

At swap meets and most nurseries, vendors have what many expert collectors call "introductory cacti"; that is, cactus varieties that are common and easy to grow.

Most of the introductory public just wants to see flowers, but serious collectors don't care about flowers. They care about the species and the form of the plant and staging it in a wonderful pot. It becomes more like a sculpture. One collector I talked to told me that he'd seen grocery stores go so far as to glue flowers on the top of cacti -- flowers that don't belong to the cacti, of course -- but they glue them there so that the cacti will sell. That's just bizarre.

And speaking of bizarre, here's an interesting coincidence; call it an evolutionary mystery. The forms of many underwater plants and animals are eerily similar to the forms of cactuses. The tuna fish and the fruit of the prickly pear cactus, the "tuna fruit," look more than a little alike. Anyone who's ever seen a sea urchin knows that they would seem right at home on a sand dune. In fact, the rolling sandy bottom of the ocean even looks a little like the desert. So what gives? The wettest and the driest ecosystems on our planet have developed almost identical shapes and forms. Weird. (Cue the music from The Twilight Zone...doo-di-doo-doo, doo-di-doo-doo....)

At one point, Knapik gently took issue with the name of the cactus club. He said, "Back when I was president, I asked them if we could change it, and they said no, it would be too hard to change the paperwork. But it should be 'The Cactus and OTHER Succulents Society.' Because cacti are succulents."

Cacti are succulents because they remain succulent (moist) in the most arid conditions. Many varieties of cactus are edible, and some would even pun that they are succulent in salads. In the plant world, succulents store water in their stems, leaves, or roots. It wouldn't be too much of a reach to call cacti (and other succulents) the camels of the plant world.

The spines on a cactus are a modified form of leaf. The spines are designed to protect the cactus's new growth from the pounding desert sunlight and to regulate water loss (more on this point later). The spines also often keep the cacti from being eaten by desert animals such as the bighorn sheep. Many cactus spines are more like hairs than thorns, and in some cactuses these hairs grow coarser and coarser until you'd rather pet a porcupine than toss a cactus-football. In fact, the cactus is like the porcupine of the plant world.

Neither the spines nor the succulence of cacti is a defining characteristic. But the areole is. The areole in a cactus is a highly specialized, cushionlike tissue structure out of which the spines and flowers grow. No other plant in the world has one. Toughened, hardened, and drought tolerant, all cacti are succulents, but not all succulents are cacti. Which is to say that cacti store water, but other water-storing plants don't have an areole that grows spines.

Cacti take the thorny crown as the most popular of the succulents. People champion cacti for their brilliant flowers, unusual shapes, and the fact that, in pots at least, they grow slowly and take up little space. Cacti are also generally easy to care for and can survive long periods of neglect. In fact, a cactus is a veritable model of resiliency.

Cacti generally have fleshy stems, brilliant flowers, and spines instead of leaves. Often, terms such as "skin," "flesh," "hair," "spine," "joints," "cuticles," and "ribs" are used to describe cacti, terms we also use to describe people. It's as if the cactus is the human being of the plant world.

I asked Knapik to list a few of his favorite cactus groups and to tell me why he thought they were exceptional.

"We have one cactus along the border of our country," Knapik began. "It's called Ariocarpus, and it's one of my favorite cactuses because it has no spines. It has these very modified tubercles where the spines normally would have come out and little wooly tufts. They look like stars. They're absolutely stunning. It's an untraditional cactus, and people are usually surprised how beautiful and symmetrical they are. I've seen them in habitat, and when you find one, it's like you've found gold."

Knapik went on. "The Astrophytum group has beautiful forms. The bishop's cap is a famous Astrophytum that doesn't have any spines, and it's shaped like a star, and it has this white flecking all over it. The Japanese have revolutionized the Astrophytum group with some of their hybrids. They've produced a hybrid called 'Super Kabuto' -- and there are clubs in Japan that focus only on this hybrid -- and some of these plants sell for thousands of dollars. They look absolutely fantastic.

"My other favorite cactus is the Copiapoa," said Knapik. "I've been to Chile three times to see them in habitat. They form mounds that are four or five feet tall and ten feet across, and the body of the plant is bluish gray, and their spines are black, and the number of heads could be hundreds, and they can live to be 500 years old. And they're fantastic. They're absolutely the most stunning plants I've ever seen in the wild. I go to Chile to photograph them.

"The Lophophora group are also very advanced and very beautiful," Knapik concluded. "This is the peyote group, and they've developed alkaloids in their tissue, which prevents animals from eating them. They've gone beyond spines; they don't need spines anymore. It's a beautiful plant, but unfortunately most of the species are banned because of the drug implications."

Because of "drug implications," Lophophora williamsii (common name "peyote") can be cultivated and kept only by Indian tribes. As you might guess, Southwestern Native Americans and cacti have a long history together.

I called around looking for a specialist who could paint me a picture of that history, and I found Richard Carrico. Carrico teaches part-time at San Diego State in the American Indian Studies Department and also works on environmental impact reports for a bioconsulting company.

How did Carrico come to be an expert on Native Americans and cacti?

"I've published books and done research," he said. "And over the years I've hung out with a lot of healers and shamanistic people and folks who use the local plants, like Jane Dumas, who's a local Kumeyaay practitioner and healer. I've learned the plants, taken the drugs, and done what I've had to do to learn how the environment was used by these folks."

I wanted to know how today's Native Americans put cacti to use.

"With a few exceptions," Carrico said, "anything I'll tell you about how Native Americans used cacti 2000 years ago will still be true today, at least in some places, especially south of the border. Near Tecate, there are certain villages where the people still live essentially in the prehistoric period."

Carrico told me that the Kumeyaay used cacti for multiple artistic purposes. "They used the big spines off the big cholla for tattooing," he said. "They would dip the spines into dyes, and the women especially had a lot of face tattooing under their chins." Then Carrico mentioned the Kumeyaay rock paintings in the county, called pictographs. "The Kumeyaay would use the mucilage from cactus as a fixative, to make the paint stick to the rocks."

And what about medicinal uses? I'd read that cacti and other succulents were often used to cleanse the skin and as an antibacterial agent. It's said the juices of various cactuses prevent infection and promote healing.

"In general," Carrico said, "you start with the big pad of the prickly pear cactus, the nopales, which the Indians would clean and peel and fry. They would cut it in strips and dry it. They would get a liquid out of it to make a beverage. People would ferment the cactus juice, and then it's supposed to have some curative capabilities as well. I've certainly eaten my share of cactus and drunk the juice."

But the clear winner for "Best Use of Cactus" has to go to the Indians of 200 or so years ago who lived near where Highway 94 and I-15 currently meet. "The place was named Chollas because of the cactus," Carrico told me. "There was an Indian village there that the Spaniards contacted in the 1770s, and the reason it was called Las Chollas by the Spanish was because the Indians had planted and cultivated and maintained a big cactus barricade around their village. So one use of cactus was as a barricade to keep other people out, as a kind of bulwark."

Which makes cactus the fortified defender of the plant world.

Their leaves are prickly spines and their bark is waxy flesh, but cacti grow fruits and flowers, just like other plants. In many cases, cactus fruit is edible. In some cases, a lot more than the fruit is edible. Edible cactus pads ("nopales") are popular throughout Mexico and Central America. Nopalitos are soft and crunchy, like okra or jicama. They're good in salads and remind me a little of some kind of tart bean or bell pepper. Apparently, cactus pads are full of vitamins and minerals as well.

I've eaten the cactus salad at El Agave Tequileria in Old Town, and I found it tasty. I called the chef there, Juan Carlos Gomez, and asked him how to prepare cactus.

"The cactus we make into our cactus salad is nopales," chef Gomez said. "When it comes to us from the Mexican market, it still has its spines, so we have to be careful and wear some kind of gloves. You take every pad of the cactus, and with a knife, you take out all of the spines. It doesn't take that long, just 20 to 30 seconds for each pad of the cactus. It's kind of like cleaning a small fish. And after you take out all of the spines and cut out the places where the spines come out, then you cut around the edge of each pad, and it's ready to be cooked in water. We boil the pads with salt for about 20 to 30 minutes. And after that, it's done. We mix the cactus with tomato, onion, and cilantro and then add some lime juice, and that's it."

As if all the unusual individuations of cacti weren't enough, these plants don't even breathe like other flora. They can't, because if they did, then the desert sun would kill them. Without getting too scientific, we might think about it like this: in order to photosynthesize, most plants exchange water and gas with the environment during the daytime, opening tiny holes ("stomata") on their leaves. If cacti did this during the heat of the day, all their water would evaporate, and they would shrivel and die. Instead, cacti open their stomata at night, bring in carbon dioxide, and store the gas as an acid. To photosynthesize, they must wait for the morning sun. Because cacti gradually fill with acids overnight, a morning cactus will taste sour, whereas an evening cactus is sweet. So if you're starving in the desert, and you're willing to risk a bloody fist or two, then you should harvest your cactus feast during late-afternoon hours.

The John James Audubons of the cactus world, the Lewis and Clarks, the Christopher Columbuses, if you will, were Nathaniel L. Britton and Joseph N. Rose, or, more simply, Britton and Rose. In 1919, Britton and Rose published the great seminal work for all cactusdom, The Cactaceae. People who've read The Cactaceae are surely die-hard cactologists.

Jon Rebman owns all four volumes of the Britton and Rose work, as well as dozens of other cactus books besides. Rebman is a taxonomist and is also the curator of botany at the San Diego Natural History Museum.

I went down to the museum to visit Rebman in his element, namely, among thousands of stacks of folders filled with plant specimens. Rebman's been at the museum for over ten years, but cactologists before him began a large cactus collection there, thousands of plants. The museum's plant collection numbers over 165,000 specimens, and it dates back to the 1870s.

In each folder in the collection are cuttings of specimens, photographs, and a few words documenting and identifying a particular species in a particular place at a particular time. Making archival-quality specimens of cacti -- cutting, flattening, bathing in alcohol, drying, and gluing multiple segments of spiky stems onto acid-free paper -- can be a "painful and bloody experience," according to Rebman.

But, like Adam in the Garden, Rebman the taxonomist scrupulously collects, catalogs, studies, cross-checks, and, finally, identifies the species or names a new species of plant. According to my trusty Oxford dictionary, taxonomy is "the science of classifying plants, animals, and microorganisms into increasingly broader categories based on shared features." To determine the shared features of plants, Rebman must call upon a tremendous knowledge of what plants exist, what they're like, what they're called, and what qualities link or separate them. He must trace lineages and study features. And after months of checking through the annals of plant history, he may find that he has a heretofore anonymous member of the kingdom Plantae; then he'll land on what seems like an accurate genus and submit the information about the new species to a professional journal for peer review.

"A name should arise from an understanding of the evolution of a species," Rebman said. "And before you name something, you'd better be certain that it hasn't been named already."

Unfortunately, over the years, not everyone has followed this sage advice. For the 2000 or so species of cacti that exist, there are over 12,000 names. This hyper nomenclature is due partly to overzealous early hobbyists but also to the fact that scientists recently began changing names based on how DNA affects ideas of what's related to what.

The species name can come from anywhere: from a distinctive characteristic of the plant, from the place where it was discovered, in honor of someone important, or you might even name a plant after yourself. "But that's a faux pas," Rebman assured me. I suggested that it might be a good idea to name a plant after someone else who names plants. Then that other person might feel obliged to name a plant after you. "That might work," Rebman said laughing.

Rebman has dubbed about ten species in his career -- five names accepted by his peers and five names pending -- and he's in the process of christening quite a few more. Rebman's personal goal is to name a species a year. We're "far from understanding our biodiversity," he says.

The biodiversity in San Diego County is unmatched in the United States. Rebman told me that 2315 different plant species are native or naturalized in our county. "That's more than many whole states," he said. (Incidentally, a "naturalized" plant is one that, although it may have been brought here by a human being, now reproduces and grows in a natural environment on its own.)

At his home, Rebman has a xeriscape that includes 150 or so cacti and succulents. (That positively succulent word, "xeriscape," means "dry landscape." Rebman's xeriscape comes complete with rocks and sand and nothing that you wouldn't find in a desert.)

At one point, I detected a prickly tone in Rebman's voice as he mentioned cactus hobbyists. What did a scientist think of our typical, average cactus enthusiast? "Today's hobbyists are different from the hobbyists of yesterday," Rebman said. "Most of them are very respectful of habitats and delicate species, and they often take very good pictures of specimens in the field. But hobbyists can also be a problem to rare species. Something that's rare gets a higher value on the market, and then those rare things can get compromised."

Rebman and I took a walk across the street from the museum, into the Balboa Park cactus garden. Now, I'd been to the rose garden on Park Boulevard a half dozen times before I even knew there was a cactus garden just a few yards away. But the cactus garden is a thousand shapes better and more interesting than those more or less uniform roses. Maybe it says more about me than it does about the plants, but the cacti speak to my imagination more clearly than the roses. Roses are fluff and fuzz and bubblegum, unicorns and fairy tales, velveteen and toy balloons. But cacti are drama and truth, philosophy and fortitude, sobriety and severity.

"Only some of the plants you see here are cacti," Rebman said. "But they're all cactuslike. The thing is that, because of convergent evolution, many plants that aren't cacti have grown to look like cacti over time. Their forms have converged. There are lots of plants that, if they weren't in flower, I wouldn't be able to tell whether they were cacti or not."

Rebman began pointing out how certain euphorbias, for instance, have grown spines, waxy skin, and ribs, just like their cactaceous counterparts, but the euphorbias are from a different part of the plant kingdom and have no areole, so cacti they are not.

"Spines on cacti are like hairs on arms," Rebman told me. The skin where a person has hair "dries last because the hair sets up a barrier to water loss. That's one function that spines serve for a cactus. So the spines set up a gradient -- from the high humidity of the plant to the low humidity of the desert -- to slow water loss to the environment, controlling the rate of diffusion."

When we came to the chollas in the cactus garden, Rebman raised his voice melodramatically, "Watch out for glochids!" He was only half-kidding. He showed me how chollas have tiny, hairlike, almost invisible spines in between their bigger spines. "Those little hairs are called glochids," he said. "They're far worse than regular spines." He led me over to a fluffy-looking cactus with no spines at all. He said, "This plant looks relatively harmless, doesn't it?" And I agreed. Then he brushed a pad of the plant ever so gently. "This would be the worst plant in the whole garden to fall into." He showed me his finger. All over the tip of his skin were tiny, brownish red, bristly, hairlike spines: glochids. "These are just like fiberglass but even harder to clean off. You'd find glochids on your skin for days if you fell into this plant, and the worst part is, it looks so friendly! They should put a warning sign up. It probably gets people all the time."

Ironic that the friendliest-looking cactus in the garden is actually the meanest. The more I looked at these wonderful plants, the more I couldn't resist falling prey to what, in philosophy and poetry, we call "the pathetic fallacy." That is, I kept imagining human traits for these humble yet prickly plants. I mentioned something about the pathetic fallacy to Rebman, and I was grateful that he didn't laugh at me: he'd never really imagined any humanness for these plants he admired so much, but he could see why I might. The only humanlike trait he added to my sense of cacti was when he told me that "a cactus will take a bullet just like a person, because of the thickness of their skins and all the water in them." Great. So now I could picture a cactus gunshot and bleeding.

Eventually I found myself identifying with cacti in the profoundest way. That is, I pictured not only human traits but my own personal traits (and traits that I wish I had) played out in cactus facts and gestures: the way they had to cling lovingly to the rare thing that sustained them (water); the ways they worked to turn the most stark and uninviting environments into comfortable homes; their witty innovations (on the leaf) and the ways that innovation had rendered them untouchable (covered with spikes); their unwavering silence, as in you'll never hear wind whispering through a cactus.

What hasn't killed cacti has indeed made them stronger and more distinctive and more beautiful as well. We all can only hope for the same rewards through our own adversities. But who among us can manage to be a cactus in the person world?