botanizing

In the field

I’m doing fieldwork for the next few days and will not post until I return.

The photograph is Cedar Mountain on the San Rafael Swell in central eastern Utah.

Substrate

I’m drawn to white substrates by the possibility of finding blazing stars (Mentzelia).  Both gypsum and limestone make substrates white and both can exclude some plants, providing a haven from competition for blazing stars, which, I’m beginning to think, can grow on just about any nutrient-poor, thick-crusted soil that creates a bad environment for others.

Here white hogbacks tucked between brown hills and a series of rufous hogbacks that tilt west above Comb Wash toward Cedar Mesa.  I walk a gully between brown hills toward the white.  The vegetation is sparse and repetitious—just the ubiquitous shadscale with its crusty leaves, a shrubby buckwheat, and the orange-flowered globe mallow.

The white hogbacks have a spine of blocky stone.  I walk the backbone stepping on and around the stones.  I’m not good at deciphering stone but guess that this must be limestone.  The vegetation is sparser here even than it was among the brown hills.  The shrubs—dark blackbrush, sage-colored bitterbrush, and thin candelabras of Ephedra—are scrawny.  There is little else except a white-rayed sunflower—Chaetopappa, which is the only thing with any remaining flowers.  There are no blazing stars.

I climb down a deep ravine and then up into the rufous hogbacks to the west.  In a narrow gully, wide enough only for one foot to swing past the other, where I can touch the substrate on each side, the steep western face is whitish and the more gently sloped eastern face distinctly red.  The red face is sculpted—a garden of Gothic forms:  spires and flying buttresses.  This miniature garden, in high relief at small scale, is a living crust on the soil—it’s called cryptobiotic—and is composed of algae, fungi, lichens and mosses and, undoubtedly, other varieties of microbial and nearly microbial life.  Here its colors offer sharp contrast: black and white on the rufous soil.  In contrast to the checkered crust on the rufous slope, the steeper west-facing white slope lacks the cryptobiotic crust; it crumbles under the touch of my fingers. 

The white face has a pack rat midden in a hollow under a large rock.  I climb past the midden, a steep, sweaty endeavor to the hogback rim.  Chert-like stones line the rim and I wonder whether the earlier cultures to inhabit this region used these stones to shape tools and projectile points.  The heat is intense, and I walk slowly down the gentle slope to a wash bottom, where the substrate is gritty and the shrubs are larger and greener. Substrate is sustenance—I’m getting hungry and think about the possibility of lunch in nearby Bluff; my pace picks up.

Sand Wind

One of the sensual incongruities of language has weather called “low pressure” pushing forward hard, aggressive wind.  It’s coming from the south. 

I was camped on a bench above an arroyo in the landscape of hogbacks and mesas west of the Henry Mountains.  I braved the wind through the evening but retreated to the canopy of my truck at darkness to read the New York Times.  The wind would have delivered the newspaper to Hanksville in seconds.

The wind gusted through the night, buffeting the truck, and kept me awake.  When I rose in the morning, I walked a couple of miles in the local washes before breakfast.  After climbing to a hilltop, a strong gust nearly toppled me into the gully below—it would have been a long, rough fall.  I spread my feet and leaned with uncertain balance into a sustained gust.  Even in the wash, the wind rushed over the ochre hills to spray my face with sandy grit. The sand wind swept around my glasses into my eyes and filled my mouth.   I ground grit with my teeth for the rest of the day.

When I returned to the truck, the telephone rang.  No, of course, it didn’t.  It was the wind ringing around my truck canopy.  I’ve noticed before this mimesis of the truck’s canopy.  It can scream shrilly in the most haunting places or simply whistle when I want to sleep.  I’m frequently taken aback in some out of the way place when a person hollers at me as I step from the truck only to realize with the successive second and third hollers that it’s the wind zinging on the rim of my singing canopy.  This should be pleasing, I suppose, for when my conversation with myself drifts to the point of repetitiveness, I can at least sing along with my truck.

One reason not to have breakfast before my walk was reluctance to use the stove in the wind.   The vegetation, although sparse, was extremely dry; the wind was simply ferocious.  I wanted to be extra cautious about fire danger.  When I returned to camp from the walk, I was, however, ready for tea.  I built a three-sided enclosure behind a rock using my cook-box and two plant presses, then set up the stove, which lit with the first match, and on went the kettle.

I sat on the rock to peel and eat an orange.  The peels dropped at my feet were encased in dust by the time I finished the orange. I foolishly opened yogurt, thinking about the texture that sand would add, but at least it didn’t require chewing grit.  After the yogurt, I huddled as closely as possible over the stove enclave to help block the wind.  Boiling time on my stove can be sensitive to even a breeze, and, in this wind, I imagined the heat flowing out in an invisible torch parallel to the land and hardly touching my kettle.  As I shielded, the hair on my left hand melted away.  It took I’m sure—surely not imagined, surely not the watching of the pot—30 minutes for the water to boil.

I drove down the mesa and to a gap in a line of yellow cliffs where the road passed; here tumbleweeds had assembled to fence the road. In the valley below the yellow cliffs, the road went north on the wind’s vector.  In this badly overgrazed place that was filled with dried stalks of weeds, the soil lifted readily in the wind, forming fast ships with curved keels that overtook me along the road.  I watched them coming in the mirror and closed the windows quickly.

By the time I reached Hanksville, where the weekend boaters on the way to Lake Powell leaned into the wind and squinted against the gusts, the sand, which surrounds the town, had largely lifted into the air—this landscape of loose sand flats and dunes was moving quickly—and the sky had yellowed.  Topography had disappeared. Cliffs had diffused and lost relief. There were no mountains on the horizon.  There was no horizon.

Textures of Stones

The thumb always appreciates a smooth stone.  The best stones I ever found were smooth and blue, appealing to thumb and eye.  When I found them at low tide at Clallam Bay on the Olympic Peninsula they were smaller than dimes, but these intertidal stones loom larger now, swelled with pleasures invested in them.

Every texture is a story.  I rub my thumb across the surfaces of stones to read histories, myths, and modern fictions.  A rugose stone recalls a labyrinth, and I see Theseus not only in search of the Minotaur but also his abandonment of Ariadne.  Just a rugose stone, it projects the labyrinths that extend from our actions, where every dead-end corner, where pockets of dirt have accumulated, is labeled hubris.

Gold patches, no matter how rough and flaky the rest of the stone, promise hope, it’s the drama of fiction. Smooth red stones turn brown and take the texture of old milk if you take them out of the desert.  They are morality tales that rely on shape-shifting to teach the consequences of theft and deception.

Slickrock is a textural mirage.  The eye, duped by sinuous curves seen at a distance, assumes a smooth surface, but slickrock is more sandpaper than ice.  Rough. Consistent, unless you find a cross-bedded surface; there the textured layers meet at sharp angles.  The rhythmic texture of slickrock becomes dissonant at the cross-bed. 

It would be simple to accuse black stones of hiding texture in stolen light.  But the black cloak is insufficient to obscure texture.  A pitted black stone will cast cups of yellow light.  Smooth, black stones with sharp angles—like obsidian—wield swords. Even coal in desert light appears to have a surface of dew. In the desert, black stones are my favorites.  They are like listening to Dante read aloud.

Welcome!

I’d like to welcome those of you who’ve just found your way via negativa to botanizing.  Thanks to Dave for offering today botanizing in his smorgasblog on the sidebar at via negativa.

To the Edge of Night in a Claw with Hoodoos

A headhunter has turned to stone while holding stone heads in his grasp.  In this place in central Utah, a sand-capped mountain range has seeded buttes along its margin.  From one of these buttes, a flesh-colored arm extends, and at its end is a grasping claw that holds a handful of hoodoos. These hoodoos are anthropomorphic stones—natural gargoyles—that have rounded heads atop belted torsos—they have been sculpted from sandstone fins by wind. I chose, instead of a tamarisk thicket at a cow pond, to spend a night in this claw with hoodoos.

The claw reached into Mussentuchit Flat—a flexured sand plain that lies between abrupt, striped buttes. I walked from the claw to survey the vegetation.  The only flowers were those of a mustard, pepper grass, whose globular panicles of white dotted the flats. Fresh seedlings of Russian thistle made pink crosses on the sand.  The vegetation was sparse and low—only the needle grass, which was obscenely green in this sage-colored place, stood much more than a foot tall and waved, like a shredded flag, the needle-like awns that stood-out in the wind from its fruits.  The rest was rounded mounds of shadscale and clumps of Indian rice grass that sat on little, sand hummocks.  There were two small toadstools that had dried to the color and texture of bone and nearly its hardness.  There were also two species of loco weeds—each looked like the dirty end of a wet mop.  The loco weeds had been nipped by cows.  One grew amid the rice grass on a low slope covered by black gravel.  It held its fruits erect and at the end of each was the dried, bent relict of the style.  These fruits had reddish splotches and scabrous hairs, which together in the sun gave the fruits a pinkish gleam.  The other loco weed was darker green and had smaller leaflets and fruits than the first.  When I squeezed its fruits, they were rubbery, and they, too, were hairy, and reflected the sun in little silver streaks.

I sat in the claw of hoodoos in the shade cast by my truck to have a dinner of turkey and Swiss cheese on a tomato and basil bagel.  Afterward, I had a cup of tea.  When the sun fell behind the western ridge, the wind came up, gusting under and around the truck.  The wind checked my form; it pressed a mould of cold air against my legs.  A huge, greenish-yellow beetle whirled past my chest with the tone of helicopter and the speed of a jet.  It impaled itself by its proboscis in the canvas of my chair; it stuck straight out and didn’t move.  I extracted the beetle from the chair and got its feet under it.  Eventually, the beetle flew—but it yoyoed repeatedly out and back from darkness to the lamp beside me.  It zipped suddenly to the open sketchbook that lay in my lap, landing beside the sketch I had made of it while it was impaled in my chair.  Had I closed the notebook both beetle and sketch would have lain side by side ever after.  The beetle flew—a solid TINK marked its crash against my chair’s metal frame.

When I stood to go to bed, my shadow, cast over the claw, was clipped at the waist—my torso disappeared in the darkness among the hoodoos.

Seeing an old friend

The loose sand was a bog even in four-wheel drive.  The road was well used, well churned by traffic, and graded from the margin of a wash.  There must be occasions—the infrequent deluge—when the wash recovers the road, but not this dry year.  Although I drove slowly, chalky dust from the dried sand made a plume behind me.

I had camped at the end of this wash in the Mohave Desert.  The sun was hardly above the hills to the east when I started the drive out.  That’s when I saw an old friend tucked against the cliff at the far margin of the wash.  The old friend was the rock nettle (Eucnide urens), an endemic of the Mohave Desert.  This species of rock nettle likes habitats that are hard against rock.  This robust clump—two feet high and four feet long—had inhabited the seam between the wash and the cliff.  I have seen Eucnide urens tucked like tongues in mouth-like clefts of vertical stone—the plants rooted only in a black crack throat.

It was 20 years ago this month that I finished my PhD dissertation on Eucnide—it is always a pleasure to see them in the field.  Eucnide is a genus of slightly more than two handfuls of species of the southwestern U.S. and Mexico.  I had studied the role of developmental evolution in the diversification of flower forms characteristic of the genus.  The research tested ideas that early phases of development were more stable than later phases in the course of evolution; I was especially interested in the possibility that modifications instituted early in the course of development could lead to major, but not necessarily disruptive, changes in form. 

The eucnides were wonderful, showing a range of ways that flower development from its very earliest phases could be modified by evolution.  Within that range of early developmental modifications were changes that had substantial effects on the eventual functional form of the flower, but there were also slight modifications of proportions and growth rates instituted at the very beginning of development that resulted in more subtle changes in those functional forms. The eucnides were especially fascinating because the opening of the petals was very labile to evolutionary change—and these modifications affected the way that petals stood in the open flowers.  These variations in petal stance make some flowers look like deep funnels, others like pin-wheels, and still others like tubes, and the differences in shape may have been variants selected by different pollinators, which would have effectively provided the reproductive isolation of the novel forms that set them off on their own evolutionary trajectories.

One of my favorite pieces of the Eucnide story involves self-pollination.  We think often of flowers as being cross-pollinated; that is, the female reproductive structures receive pollen from a genetically different individual.  Self-pollination occurs when the female reproductive structures are dosed with pollen from stamens in the same flower or from another flower of the same individual plant.  Among the eucnides, species that have large flowers have forms that appear effectively to prohibit self-pollination, whereas those species that have small flowers may only self-pollinate (we don’t know yet the relative amounts of self- versus cross-pollination).  There are also species of rock nettles that have flowers of intermediate sizes that provide opportunities for cross-pollination at the beginning of their reproductive phases but force self-pollination at the end of the reproductive phase.  Among the different species that have these intermediate flower sizes, the opportunities for and timing of cross- versus self-pollination have been varied by interspecific differences in rates of growth of male and female reproductive structures within flowers.

These size-related effects may be very important in evolution.  For example, mutations that prolong development and result in larger flowers may result in individuals capable only of cross-pollination.  Similarly, mutations that shorten developmental time may result in flowers that are smaller and obligately self-pollinate.  Both are changes that could effectively isolate individuals or a group of individuals from reproducing with the rest of the population.  Again, such reproductive isolation offers the inception of evolutionary divergence between subpopulations.

We often think of cross-pollination as important because it serves to enhance genetic diversity in populations—and genetic diversity can be critical in times such as environmental degradation or pathogen infestations.  Self-pollination can also offer advantages in some environments.  For example, it can serve to perpetuate the high degree of adaptation that some plants may have evolved for local environmental conditions.  In environments, such as some deserts, where pollinator availability may depend on unreliable rainfall, selection may favor self-pollination or the mixes of cross- and self-pollination that we find in many rock nettles because those modes of pollination relax the importance of pollinators for plant reproduction.  Most of the rock nettles that self-pollinate are in harsh deserts of Baja California and other parts of Mexico.

Eucnide urens—the common rock nettle of the Mohave Desert—has large flowers and a pollination system that promotes outcrossing.  It is pollinated by large bees of the genus Hesperaspis.  Curiously, in Mentzelia, another genus of Loasaceae, the family that also includes Eucnide, there are annual species endemic to the Mohave and Sonoran deserts that have converged in evolution on flowers of roughly the same size and form as those of Eucnide urens. This convergence in flower forms between these two closely related genera may well have been driven by the large bees of the families Halictidae and Mellitidae that they share.

Rather than the rock nettles, Mentzelia now gets attention in my lab.  Mentzelia—the blazing star genus—is providing students opportunities to develop deep friendships with wonderful plants.

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The information on pollinators of Eucnide urens and annual mentzelias is from the PhD dissertation of Gilbert Daniels (1970; University of California Los Angeles).

Western Utah

In the field

I’m in the field—no new posts for a few days.

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The photograph is Caulanthus crassicaulis in the Spring Mountains of southern Nevada.

Nothing Here Worth Your Life

“If I had half your money, I’d rebuild this town,” a man said to me. I wondered whether he thought that everyone from outside this dying town had money.  He wore an orange t-shirt—a railroad employee—and sat in a white pick-up.  As he talked to me, he dribbled tobacco juice into a plastic orange juice container.  I was making a photograph of Lund’s general store in Modena, which is almost a ghost town.  “I’ve seen a lot of people take pictures of that building,” he said.  “When I was a kid we took the train here.  I had ice cream sodas at Lund’s.  I went back in there a few years ago.  Found an 1894 silver dollar under the counter.”

The western end of the Escalante Desert, where Modena lies, constricts between mountains.  It’s been squeezed—squirted-out. Emptied and eroded.  Its windows have shattered.  Its roofs have fallen.  A sign on one derelict building threatens:  “There is nothing here worth your life.”