Joshua Trees, Taxonomy, and Divorce

Moving into my little house in the desert hasn't been complicated. The place comes furnished, and so taking possession basically means carrying boxes of books from the Jeep into the living room. It's hot, even for July, and the summer of 2008 is shaping up to be warmer than usual. I have spent an inordinate amount of time sweating. I am covered in dust from my boxes of books. My sweat catches the dust, carried it in muddy saline rivulets into inconvenient and uncomfortable places. Showering helps only a little. The local water is hard. Shower all you like: soap never really comes all the way off. I left a half-full glass of water on my bedside table the day before yesterday. Now there's a coat of lime in the glass where the water had been.

Drinking the water, though: that helps with the heat. The water in Nipton tastes better than any other tapwater I've ever drunk. Is it the heat? The dissolved solids? Hard to say. Perhaps it's the remove from which the water comes: seven hundred feet down, to hear my new neighbor Fred tell it the other day when I picked up the keys.

Fred's an affable, wizened man in his mid-70s, rail-thin and tobacco-stained -- my new best friend in this wide spot in the road calling itself a town. He's lived just about everywhere in California over the last half-century. He speaks in a flat twang that seems to comes from Oklahoma, though maybe it just comes from Fred. He uses the phrase "and everything" the way other people use punctuation. I've never seen him without his straw cowboy hat. That hat is well-worn. It looks as though Fred had run it over with his front end loader, put the thing in reverse and run over it again, and then put it out on the train tracks for a week or so. It has some character, that hat.

"Seven hundred feet down they had to drill, or at least that's what they told me, and everything."

I nodded. Aquifers around here can hide remarkably far beneath the surface.

"There's supposed to be a whole underground river down there, and everything," Fred continued. "A big freshwater river an eighth of a mile down." He paused for a second, seemingly deciding whether or not to tell me more. "Now I don't know about this part -- I'm just going by what they told me, and everything -- but they're supposed to have brought up a catfish out of that water when they drilled the well."

"Huh!" I said, noncommittally.

"Yeah, I don't know if I believe it either, seems unlikely and everything. But that's what they told me. A big old catfish. Two and a half, three feet long, swimming around down there for who knows how long and everything."

I wanted to believe Fred's story, so I tried for a few minutes to imagine a deep, black stream an eighth of a mile beneath the creosote, sunless still and silent. A compelling image, but it didn't take.

It's just a few boxes in this Jeep load, but the heat is getting to me. I take a break after box number three and drink a pint of that mythical catfish's domain. Maybe it's the water's age that makes it taste so good. Down there fifteen thousand years, rain that fell back in the Pleistocene and stayed hidden, it had avoided the whole of documented human history up until the point just now when it came out of the tap in my kitchen. Take a drink most places and those water molecules may have cycled through a few dozen people, or a few hundred. Drinking this ancient water feels like going all the way back to square one.

Which is what I'm here for, isn't it? I head back to my dusty boxes of books, promising myself that once I got them put away I'd head for the Joshua trees a few miles east.

It is a promiscuous dust on my boxes, delivered unto them out of a number of different vintages, different landscapes. Some of the dust on my boxes got there as I packed them over two months, whole rooms taken up with half-filled boxes in what I was already starting to think of as "Becky's house." Some of the dust settled on the boxes after I'd driven them to Barstow, stacked them in the leaky storage locker I'd rented there, where they'd for sat a month and a half until I got the key to my new house. And some of the dust added itself between Point A and Point B. The sky was brown in the San Joaquin Valley -- plowing season -- and airborne topsoil insinuated itself into my belongings as I drove. Once I made it over Tehachapi Pass and descended into the Mojave, the whole desert was aswirl in dust devils. The bed of the Mojave River rose into the sky to settle over everything a few miles downwind. My boxes are covered with a thin transect of California soils, all of them from landscapes turned upside-down: the desert, the Central Valley, my marriage.

Each box bears a scrawled label, with which I attempted, while packing, to describe the contents clearly and quickly. This was more difficult than I had anticipated. When divorce became inevitable and it was clear I was leaving, I started giving books away almost frantically. Most of what I owned was books, and I gave away hundreds of them. The books I knew I'd never read, or that I'd never read again, the books I'd never wanted in the first place and the books I couldn't bear to part with that I parted with anyway as an exercise in detachment, books given to friends I thought would like them and books given to the thrift store and books given back to the friends I'd suddenly remembered I'd borrowed them from some time ago, truckloads of books, backaches of boxes of books, and when I looked at the remainder, when I looked at the bare minimum of books I figured I'd need in my new life as a desert refugee, it was as if I hadn't given any away at all. I bought two dozen big boxes to pack them in, and I ran out of boxes and went and got more.

Because I had a few weeks in which to pack, I tried to organize my books in a way that made sense, labeling each filled box with concision in three-inch magic marker. At first it was easy. Boxes labeled by author: Stegner. Abbey. McPhee and Gould. Boxes labeled by type of book: "Field Guides." "Cookbooks." Boxes labeled by subject: "Paleontology." "Birds." "Peru." Before long my taxonomy started to break down. A thousand diverse books left unpacked and yet there weren't enough of any one type to fill a box. I began to resort to makeshift categories. "The stuff that was on the hall shelves." "Potentially useful reference works." Before long even those less-informative categories didn't quite work. Which is why, along with the boxes labeled "Desert Field Guides" and "Desert Biology References" and "Southwestern History" and the like, wedged into the back of the Jeep, is a box labeled "Miscellany."

After six weeks I don't remember what I put in there; I figured, puzzling over it in my superheated storage locker two hours ago, that I could use a surprise. One by one I haul the remaining better-labeled boxes from the white gravel driveway, stack them in the living room next to my makeshift desk, then slide the mysterious seventh box out of the Jeep, close the rear hatch, carry the box into the living room and put it on the coffee table. Grabbing a knife from the kitchen I slit the packing tape and open the box. Inside are three books on web design, several power strips and extension cords, a thesaurus, a cast iron skillet, two heavy winter shirts, my late dog Zeke's last collar (with tags still attached), a container of Lapsang Souchong tea (loose-leaf), and a teapot.

I make myself some tea.

Once the tea has steeped I pour most of it into a travel mug, fill a half-gallon bottle with delicious ancient water and head for the Jeep. Strapped in, I hang Zeke's collar from the rear-view mirror, pull out onto the quiet two-lane that fronts my house and head east. The road is arrow straight for miles in either direction, the way only desert roads can be. Crossing the state line into Nevada two miles east of my house, the Jeep bumps over a seam in the asphalt. Zeke's tags jingle. I look in the rear-view to see if he's okay, a habit I didn't know I had until right this second, 18 months after I buried him. He isn't there behind me. He's so far behind me that I can't see him anymore. I pass a Mojave yucca at roadside -- the first since I started driving -- and then another.

My little house in the Ivanpah Valley is really an ideal place for me to have landed. Study Joshua trees long enough and one necessarily learns a thing or two about their close cousins in the Mojave Desert, the Mojave yucca and banana yucca -- Yucca schidigera and Yucca baccata, respectively. Both those species live in my new neighborhood, in a narrow band where their ranges overlap. Yucca schidigera, with its dark-green leaves an inch thick and a foot and a half long, grows from here westward through California's deserts to San Diego and Baja. Yucca baccata is built to about the same scale as Yucca schidigera, but its leaves of that pale waxy blue the botanists call "glaucous." It grows from right about here eastward to the Rio Grande. And towering above them both is Yucca brevifolia, my botanical mentor, the Joshua tree.

Those aren't the only other yuccas that grow in the company of Joshua trees. There's an odd, disjunct population of Joshuas just north of Wickenburg, Arizona that grows among plants more typical of the Sonoran Desert than the Mojave. The giant, many-armed saguaro cacti grow there among the Joshua trees, and the ocotillo with its stems like barbed wire, and scattered here and there are fine specimens of the soaptree, Yucca elata. This yucca gets tall enough to rival Joshua trees, each trunk topped with a profusion of long, bayonet-like leaves.

There was one more yucca in Joshua tree country, Yucca whipplei, the "Lords Candle" that sends up five-foot spikes of bloom to punctuate the mountains above Los Angeles, but that yucca is no more. It didn't go extinct: it got renamed. It's now Hesperoyucca whipplei that blooms in the San Gabriels.

At any rate, my house is tantalizingly close to a whole lot of yuccas, of Joshua tree and non-Joshua tree varieties. As the road climbs out of the Ivanpah Valley and into the McCullough Mountains, some of those yuccas of the Joshua Tree variety begin to appear by the side of the road. I find a wide spot on the shoulder and pull over. I walk to the Joshua tree nearest my house and introduce myself.

There are barrel cacti here, bright red-spined orbs. I learned them as Ferocactus acanthodes, and it takes me a minute to remember that they're now Ferocactus cylindraceus. Three decades or more I've been chasing these mutable Latin names in my mind, trying to keep up with all the periodic renamings. The names have been changing since the 18th Century biologist Carolus Linnaeus developed the binomial system of taxonomy we now use, in which each species is denoted by a generic name (Yucca) modified by a specific epithet (brevifolia), that genus and species being the two basal taxa in a hierarchy in which each genus is contained in a family, each family in an order, each order in a class in a phylum in a kingdom.

We're in our third century of name changes so there's a lot of keeping track to do. That said, the Joshua tree's botanical name hasn't changed much lately. For a brief period after botanists "discovered" the tree in the 19th Century it bore the botanical name Yucca draconis -- Dragon Yucca. Tragically for all of us that name was later ruled invalid: someone else had already claimed it for a different yucca, which then had its name changed anyway. If not for the pesky rules of botanical nomenclature Southern California climbers might flock to Dragon Tree National Park on the weekends.

Biologists know two things with certainty. The first is that there are many trillions of individual organisms on the planet. Try to get more detailed than that and the boundaries get muddy. We talk of species as if they were unambiguous objects, but the entire body of biologists is so far unable to define the concept satisfactorily. You may have learned in school that the defining characteristic of a species is reproduction, that members of the same species can mate and produce fertile offspring while reproduction across species lines creates sterile hybrids, mules being the canonical example. As a rule of thumb that definition still works for most things you're likely to encounter, but glaring exceptions to the rule are also quite literally familiar. Dogs, f'rinstance, which mate shamelessly with coyotes and red wolves and then whelp squeaking litters of completely fertile hybrids without so much as a permission slip from the biology textbooks.

Sometimes the boundaries of a species are fairly clear. There's no other tree that's so much like a Joshua tree, for instance, that a good gardener couldn't tell them apart with her peripheral vision. But sometimes the line isn't so crisp. There are holes in this Joshua tree's trunk that were probably drilled by a ladderbacked woodpecker -- Picoides scalaris, a common bird hereabouts -- looking for insect borers. The closely related Nuttall's woodpecker -- Picoides nuttalli -- lives along the Pacific coast. The ranges of the two birds overlap in the southern Sierra Nevada, and where they do, the ladderback and the Nuttall's interbreed and have fertile progeny. Are they one species or two? You can tell a ladderback from a Nuttall's by sight, usually, as they bear differing patterns of black and white barred feathers. With some species, mapping out the boundaries is not so easy. Sometimes figuring out the outlines of a species is like bisecting a sneeze.

Which raises the question: is there even such a thing as a species? Or are species entirely a creation of the human mind, a way that we impose an artificial order that isn't actually there? We look at a seemingly random pattern of stars and create constellations of bears and crabs and bulls, hunters and their dogs marching across the night sky. We look at clouds and see faces in them. We find ominous and portentous patterns in tea leaves. We look at two people, strangers to each other and themselves, and declare that relationship a "marriage" based solely on their using the same bed. We seek patterns in the random assemblages offered us by the natural world. We set out boxes of our own devising and try to cram a wild diversity of things into them in an order that makes some sense to us, and then we scrawl a label on that box that may later seem insufficient or inaccessible.

What if the box metaphor isn't the best one to use? What if the better model turns out to be that buried river? The second thing that biologists know with certainty, the other big truth in the life sciences, is that all those many trillions of individual organisms spring from the same source. All life on earth, every thing that lives and has ever lived, every bird and beetle and box elder tree shares a common ancestor. We are each and every one of us related, each and every one of us the front of an impossibly ancient flood of genes rising from a single spring. We are the foam and spray of a river flowing out of deepest time.

When Linnaeus invented his binomial taxonomy he -- and most everyone else -- thought species were unchanging, decreed by the Creator at the start of time. We know better now, or at least most of us do. Species, whatever they are, evolve. They arise out of older species, change, split into two or more daughter species, wink out of existence. They are fluid. Their boundaries are imprecise and occasionally arbitrary. They're more like shifting channels in a braided wash than they are the well-defined pigeonholes Linnaeus imagined.

And thus over the last half century or so taxonomists have struggled to transform their work away from the exercise in "stamp-collecting" that was Linnaeus' legacy, an obsessive cataloguing and naming of diversity for the sake of diversity, in the fashion of collectors of beer cans or baseball memorabilia. Instead, taxonomy is becoming a form of genealogy; a way of labeling an organism's place in the grand family tree of all life on earth, and its familial relationship to every other living thing. The label applied to your species is, more or less, shorthand for the names and descriptions of all your ancestors. It is the two-word version of the history of life leading up to you -- or at least to your species.

The precise chain of relationship that links me with this Joshua tree is a matter of objective fact, though much of that fact is likely forever obscured. Each of us has just one accurate way to trace our chain of mothers back to the one we share, and the fact that I can't trace my own back beyond the Nineteenth Century doesn't change that. Individual organisms are easy to grapple with: we're born, we reproduce, and we die. Just as defining a species is harder than defining an individual, describing a species' history and ancestry is more complicated than describing one organism's life history. It may be that we'll come up with a more flexible and accurate system of naming that more closely reflects the fuzzy biological reality on this planet.

Until then, the proper definition of a species is always going to be somewhat subjective. Biologists will always argue over the boundaries, membership, and history of the species they study. It's not contrariness -- well, not just contrariness -- but an ongoing, consensus-building argument over which set of arbitrary assumptions is the most useful in understanding life's family tree. They might argue that a species has been assigned to the wrong genus. They will argue that a species really ought to be absorbed into another, because not enough distinguishes the two.

And they will argue that some species should be split into two or more smaller ones. One of the boxes next to my desk has inside it a scholarly paper in which the author suggests that the eastern and western subspecies of Joshua tree be split into two species. Differences in the anatomy of flowers, and of each group's attendant moth species, seem to create an impassable barrier to reproduction between the two kinds of Joshua tree. The author proposes that the western Joshua trees keep the old name, and the eastern ones -- including this one nearest my house -- be assigned to the new species Yucca jaegeriana.

These sorts of things never get decided quickly. Counterarguments will be made. Papers will be written; doctorates awarded or denied. The Joshua trees will continue to put out new leaves, flower and set seed, produce new trees and grow old and die, and humans will continue to argue about what to call them -- each species doing what it has evolved to do, carried along inexorably in that great river of ancestry with all other living things on earth for company, and everything.

Chris Clarke is an environmental writer of two decades standing. This post is an excerpt from his forthcoming book on Joshua trees. Chris writes from Joshua Tree regularly at his acclaimed blog Coyote Crossing and comments on desert issues on KCET weekly. Read his recent posts here.