Oaxaca Journal

by Oliver Sacks, M. D.

  CHAPTER THREE

  SUNDAY

  Today we will go on a botanical foray, over the mountains to the Llano de las Flores—“the meadow of flowers”—though now, in January, we are in the middle of the dry season, and there will be no flowers. The central hills and valley, indeed, are bone-dry, desertlike, brown. (It is difficult to imagine them otherwise, but I must return, I think, in the rainy season, when it is carpeted with Rigidella, an iris with brilliant scarlet flowers.)

  We gather outside the hotel with gear of all shapes and sizes, for our high-altitude, perhaps wet trip—we will soon be at 9,000 feet or more. We have layered clothing, which we will doff, then don again, layer by layer, as we go from the tropical valley to near-freezing winter rain forest. We also bring collecting gear—mostly plastic bags for plant specimens (how different from the tin vasculums of my youth!)—as well as lenses, cameras, binoculars strung around necks. Several of us carry “the bible,” the Pteridophyte Flora of Oaxaca, Mexico.

  One young woman (she is from the local botanical garden) is carrying a plant press, and the sight of this raises questions about what one is allowed to collect. Collecting spores, we are assured, is fine. John speaks of ways of folding paper to enclose the spores—ways which are “seamless and seemly.” “Don’t use Scotch tape—the spores will stick to it!” he adds. But there are strict regulations about collecting anything else, and we do not have a license to bring plants back to the States. We may collect isolated fronds but no plants or seedlings, and we are encouraged to document everything photographically. (Almost everyone has macro lenses: I, foolishly, left mine in New York, but what I do have with me, which no one else has, is a stereo camera.)

  And there is Dick Rauh, a botanical illustrator and teacher at the New York Botanical Garden, who will draw everything of interest—both the actual-size views and his beautiful, detailed enlargements, ten or fifteen times life-size. He carries sketch pad, pens, pencils, a medley of high-power lenses, and a pocket microscope.

  Dick became a botanical illustrator only after retiring from a long, successful career as a designer of film credits, and is now nearing completion of a Ph.D. in botany, so he is quite knowledgeable about the plants he is drawing. I am fascinated by the relation of knowledge to perception, and ask him about this. I tell him of the amazing plant drawings I have seen by autistic savants—drawings based purely on perception, without any botanical knowledge. Dick, however, insists that knowledge and understanding only sharpen his perceptions, do not compromise them, so he now sees plants as more interesting and more beautiful, more miraculous, than ever before, and he can convey this, emphasize one aspect or another in a way which would be impossible in a literal drawing or in a photograph, impossible without knowledge and intention.

  It will take two or three hours to reach the meadow—about eighty or ninety kilometers distant—with stops along the way. This part of our route, along the Pan American Highway, used to be, Luis says, an Aztec highway. But we turn off the Pan American Highway after a couple of kilometers, onto Highway 175, which goes from the Pacific Ocean to the Gulf of Mexico. At the junction is a statue of Benito Juárez, with panels around it showing episodes from his life. Luis promises to tell us all about him later—his tone is one of affection and reverence. He says that Juárez was born in the village of Guelatao, which we will be passing through.

  We are now driving to the East Sierra Madre. I ask Scott about the many red flowers we pass. They are Solanum, he says. He tells me that some other species of Solanum are bat-dispersed and have greenish or white flowers, while these, bird-dispersed, have red flowers. The bat-dispersed ones waste no metabolic energy producing what would be, for them, a useless red pigment.

  Scott and I speak of the coevolution of flowering plants and insects in the last hundred million years, the development of the dramatic colors and shapes and scents by which flowering plants lure insects and birds to their flowers. And we speak of how certain kinds of red and orange fruit seem to have appeared only in the last thirty million years or so, in tandem with the evolution of trichromatic vision in monkeys and apes (though birds had developed trichromatic vision long before). Such fruits, a staple of many monkey diets, were particularly visible to trichromatic eyes in the tangled jungle foliage, and the plants, in turn, relied on the monkeys to disperse their seeds in their feces.

  The marvel of such coevolution, such mutual adaptation, is central to Scott’s interests. He and his wife, Carol Gracie, together and separately, have spent their lives exploring it. But I, though I also appreciate the beauty of such adaptations, prefer the green and scentless world of ferns, an ancient green world, the world as it was before the coming of flowers. A world, too, with a charming modesty, where reproductive organs—stamens and pistils—are not thrust out flamboyantly but concealed, with a certain delicacy, on the undersides of leafy fronds.

  Long after the sexuality of flowering plants was recognized, the reproduction of ferns remained a mystery. It was believed, Robbin told me, that ferns had seeds—how else could they reproduce?—but since no one could see these, they assumed an odd and almost magical status. Invisible themselves, they were thought to confer invisibility on others: “We have receipt of fern-seed, we walk invisible,” says one of Falstaff’s henchmen in Henry IV. The great Linnaeus himself, in the eighteenth century, did not know how ferns reproduced, and coined the term cryptogams to denote the hiddenness, the mystery, of their reproduction. It was only in the middle of the nineteenth century that it was discovered that in addition to the familiar fern plant with its spore-bearing fronds, the sporophyte, there also existed a tiny, heart-shaped plant, very easily overlooked, and that it was this, the gametophyte, which bore the actual sex organs. Thus there is an alternation of generations in ferns: Fern spores from the fronds, if they find a suitably moist and shaded habitat, develop into tiny gametophytes, and it is from these, when they are fertilized, that the new sporophyte, the baby sporeling, grows.

  Most gametophytes, like liverworts, look much the same. The beauty of ferns, their enormous range of form, from towering tree ferns to tiny filmy ferns, from the delicately divided, lacy fronds to the thick, undivided leaves of staghorn and bird’s-nest ferns—all this resides in the sporophyte form. And the sori themselves take on a variety of forms: whelks and bubicles in some species, creamy masses in others, and beautiful, fine parallel lines in bird’s-nest ferns and others. Part of the joy of ferning is in turning over the fertile fronds and spotting these sporangia.

  John Mickel loves the fertility, the sporangia of ferns. “Ooh!” he says of an Elaphoglossum, “isn’t that nice, smeared sporangia on the other side.” Of Polystichum speciosissimum: “Look at those scales and incurved margins!” And of a Dryopteris, which he has just found in the forest: “Fertile as a moose!” he says, gazing at its sporangia. John, Robbin whispers to me, jokingly, has “pteridological orgasms.” I have often seen these at our Saturday fern meetings. His voice will rise, he will wave his arms about, use the most extravagant language (comparing spores, sometimes, to caviar): “It makes one’s heart go pit-a-pat.”

  My own impulse, like John’s, has always been to cryptogamic botany; I find flowers, with their explicitness, their floweriness, a little too much.

  Indeed, many of us share this feeling, and when we have our AFS meetings on Saturdays, any mention of flowering plants tends to be accompanied by a sort of joking apology: “If you will excuse my mentioning it …” or “I know you won’t like this, but …” You might think, hearing us on a Saturday morning, that we still lived in a flowerless, Paleozoic world, where insects play no role, and spores are dispersed by wind and water only. (I should add, in all fairness, that there is equally little reference among us to plants lower than ferns—mosses, liverworts, seaweeds, etc.—and I, with my predilection for the primitive fern allies and mosses, am sometimes, I imagine, suspected of apostasy.) Of course, the particular passion for ferns is embedded, in all of us, in a much broader botanical and ecological con
text—even the most ardent of fern systematists are aware of this—it is just that we pretend at times, in a sort of nostalgia or in-joke, to have no interest in the wider plant world.

  Among my fern-loving fellow travelers, however, there are quite a few experts on flowering plants, too—J.D. and Scott among them—and now, on the bus, as we pass by some trees laden with glorious white flowers, Scott draws our attention to them. These, he says, are tree Ipomoea. Ipomoea, I query? The same genus as the morning glory? Yes, says Scott, the sweet potato, too. I think back to my California days, in the early 1960s, when morning glory seeds—one variety of them, at least (the “Heavenly Blue”)—were used for their psychedelic power—since they contained ergot compounds, lysergic acid derivatives, similar to LSD. I used to get three or four packets of the hard, angular black seeds, pound them to powder with a mortar and pestle, then—this was my special innovation—mix the ground seeds with vanilla ice cream. There would be intense nausea for a while, followed by visions of a very personal heaven or hell. I often wished for the right place and time to take it—and this would have been in south Mexico, where the morning glory grows easily and abundantly in the mountains, and its seeds, ololiuhqui, can be kept indefinitely without losing their potency. Indeed, I am told, the plant itself (which the Aztec called coatl-xoxo-uhqui, green-snake, for its twining vinelike habit) was regarded as a sacramental plant, and used in the presence of a medicine man, a curandero.

  In Plants of the Gods, the great ethnobotanist Richard Evans Schultes and the chemist Albert Hoffmann (who was the first to synthesize LSD and to report its effects), describe how every culture has discovered plants with hallucinogenic or intoxicant powers, powers often seen as supernatural or divine. But the Old World knew nothing like the powerful hallucinogenic drugs of Mexico—ololiuhqui (which the Spanish, when they encountered it, called semilla de la Virgen, seed of the Virgin); the sacred psilocybin mushroom, teonanacatl, God’s flesh (its active constituents also lysergic acid derivatives); and in the north of Mexico, overlapping the southern U.S., the buds of Lophophora williamsii, the peyotl cactus, sometimes called mescal buttons (though these have nothing to do with mescal, the distilled liquor made from the agave plant).

  As the bus churns up the mountain, Scott and I chat about these plants, and the more exotic South American hallucinogens, such as ayahuasca (the vine of the soul), made from the Amazonian vine Banisteriopsis caapí, which William Burroughs and Allen Ginsberg describe in The Yage Letters; and the trypt-amine-rich snuffs—Virola, yopo, cojoba—the way in which their active ingredients are all so similar chemically, and so close in structure to serotonin, a neurotransmitter; and the way in which they were all discovered in prehistoric times (was it by accident, or trial and error?). We wonder why plants so different botanically should converge, so to speak, on such similar compounds, and what role such compounds play in the plant’s life—are they mere by-products of metabolism (like the indigo found in so many plants); are they used (like strychnine or other bitter alkaloids) to deter or poison predators; or do they play some essential roles in the plants themselves?

  It is extraordinary to sit next to Scott on the bus. He identifies, or can identify, everything we see, and he knows every plant in its meaning and context; the whole world of evolution, competition, adaptation, moves through his mind as we pass. I am reminded of another bus ride, in the state of Washington, with a friend from Guam, and how her knowledge of geology brought the entire inorganic landscape, all the landforms around us, as we passed them, to life. She, too, as it happens, was primarily a pteridologist, but her geological eye, so well-developed, gave an extra dimension, meaning, to everything we saw.

  Accompanying us on the bus is Boone. I am not quite clear, at this point, as to who and what Boone is, though I know that he is an old and highly respected friend of John Mickel’s—they met here in Oaxaca back in 1960—and that Boone has worked here as a botanist or agriculturist ever since. He has a house for visiting botanists, apparently, high up in the mountains, near Ixtlán, and we will be visiting this in a few days. Boone must be in his seventies; he is short but broad and strongly built, agile, and has a fine head with a cowlick of hair over his forehead.

  He is evidently an expert on the trees of Oaxaca, and now, as we move higher into the mountains, and oaks and pines become the dominant vegetation, he gets up in the bus and starts to speak to us. “Most of the oaks,” he starts, “are in such an active state of evolution that they cannot be identified. Some floras speak of thirty species, some of two hundred—and these hybridize constantly.” The first pines we see have short needles and cones. Then, a few hundred feet higher up, pines with longer needles and larger cones, another species.

  Clouds on the mountaintops—fabulous vista! As we climb a little higher, Boone points out a magnificent Douglas fir on a precipitous outcropping to our left. This stand of Douglas firs was discovered, he adds, in 1994, by a botanist from the Hungarian Museum of Natural History. It is the southernmost population of Douglas firs in the world. Boone goes on to speak of Oaxaca as a uniquely rich botanical borderland where plants of northern origin, like these pines, mingle with South American plants that have migrated north.

  Other plants: Abies oaxacana. Madrones—Arbutus, with red wood and peeling bark. Indian paintbrush, orange, along the road, admixed with blue lupins and a purple lobelia. Small yellow flowers—marigolds. Other yellow flowers are dismissed as DYCs—damned yellow composites. The plants of the Compositae family include dandelions, asters, thistles, and others, where the flower head is composed of florets radiating out from a central disc. They are among the most common of all wildflowers and often difficult to identify. Bird-watchers use similar phrases: There are fine, interesting birds, and then there are the LGBs—little gray birds—flitting everywhere, distracting the attention.

  The bus climbs higher and higher, and now we get to the top of the ridge, 8,400 feet above sea level. A lumber road goes off to the left, up to the top of Cerro San Felipe. It is colder here, wetter, and more moss is to be seen. As we start our descent, we drive just a mile or two, and stop at a small gully called Río Frío. John Mickel immediately identifies a new fern, a spleenwort, Asplenium hallbergii. I ask, in an idiotic way, “Who was Hallberg?” John looks at me strangely, and says “Ask Boone!”

  Then he swoops off to another fern, Anogramma leptophylla. “This is one of the great ferns of the world! It’s full size, only an inch or two high. It’s a cutie, only occurs at high elevations.” He moves quickly to another fern, Adiantum, a maidenhair, and another, an Asplenium.

  John becomes tremendously enthusiastic over almost every fern we see, and when he was asked which was his favorite, he had difficulty giving an answer. “When speaking on fern cultivation,” he said, “I find myself citing the ostrich fern as my favorite, and a minute later the autumn fern is my favorite. In fact, I have three hundred favorite ferns. I love the ostrich fern for its great shuttlecock form and its wide-creeping runners, and the autumn fern for its red sori and dark lustrous fronds that remain standing upright and green all through the winter. I like the Himalayan maidenhair for its delicate beauty. Some of my favorites have special memories—I found the Mexican woodfern on top of Cerro San Felipe, here in Oaxaca, after its not having been collected anywhere for over a hundred years. For scientific study, Anemia and Elaphoglossum claim my vote, though Cheilanthes and Selaginella are close behind. How do you choose among your children? They are all wonderful, and the more you know them personally, the more you love them.”

  My attention wanders a bit—I see we are surrounded by sweet-smelling salvia, sage. And beautiful calla lilies in a field, in which there is a notice in Spanish which I puzzle out slowly: Anyone Who Does Not Respect This Property Will Be Jailed. Or shot, or beheaded, or castrated.

  “Here’s Pleopeltis interjecta,” John continues, “Big round sori with yellow spores,” he says, looking at the clustered sporangia, “a splendid specimen! Another Mildella, with smooth margins, M. intramar
ginalis. If it’s serrate, it’s serratifolia.” My head is spinning with all the different ferns and their names, and I move away and wander a bit by myself, homing in on a wonderful tree full of mosses and lichens. When ferns get too much for me, I need to go lower, to the simpler, less demanding forms. To appreciate this microworld one needs a powerful hand lens—we all carry these—or even (as Dick has) a pocket microscope, to see the tiny stars of mosses, the fairy cups of lichens.

  I join Robbin, who is standing by a stream. He points out liverworts, and a hornwort, Anthoceros, in which one can see a blue-green, nitrogen-fixing bacterium, Nostoc. Animals, higher plants, even hornworts, he says, may think themselves superior, but ultimately we are all dependent on about a hundred species of bacteria, for only they know the secret of fixing the air’s nitrogen so that we can build our proteins.

  “Here’s an Elaphoglossum, at last!” says John Mickel, climbing a crag. “There are six hundred species. They all look alike. This is …” He hems and haws, turning it this way and that under his lens. “This is E. pringlei, I guess.”

  Most ferns are fairly easy to distinguish and identify, by the size and form and color of their fronds, the way they are divided, their veins, the character and location of their sori, their general habitus. But Elaphoglossum is tricky in this regard. In his swift, minute, and almost intuitive examination, John must have looked at some very subtle differences, such as the form and distribution of the blade scales, characteristics visible only with a hand lens.

  When I ask Boone about Asplenium hallbergii he is tactful enough to overlook my blunder, my failure to understand that he is Hallberg, that this is a species named in honor of him: Boone Hallberg. (I had failed to realize this, or forgotten it, because to everyone here, he is just “Boone.”) I am intrigued by the mysterious Boone. I pick up fragments: He is not just a systematic botanist, Scott says. His interest has always been more in agriculture and ecology. He came to Mexico as a young man, drawn by the special needs of Oaxaca. He was especially concerned with deforestation, and tried hard to get people in different villages interested in the replanting of trees. He seemed to have a special gift for communicating with the local people directly and easily, getting things started from a grassroots level. He had been interested, too, in agricultural problems and possibilities, and especially the potentials of new sorts of corn.