Sunday, February 27, 2011

The Living Arroyo

What’s happening: People pruning trees; Russian thistles breaking loose; Russian olive, juniper and pyracantha berries persist.

What’s still green: Moss, evergreen, yucca, grape hyacinth, Jupiter’s beard, phacelia, pink evening primrose, broom senecio, snakeweed, chrysanthemum leaves; some grasses.

What’s grey, blue-grey or grey-green: Piñon, four-winged salt bush, yellow alyssum and winterfat leaves.

What’s red/turning red: Cholla, Madonna lily, golden spur columbine, small-leaved soapwort, beardstongue, yellow evening primrose, creeping mahonia leaves; rose and young tamarix stems.

What’s yellow/turning yellow: Globe and weeping willow branches.

What’s blooming inside: Cleaned and trimmed plants moved back onto enclosed porch; zonal geraniums blooming; new leaves on deciduous chaste trees.

Animal sightings: Hawk, rabbit; mouse trying to get into house.

Weather: Winds; snow lingers in Jemez and Sangre de Cristo; last snow 2/4/11; 11:01 hours of daylight today.

Weekly update: Sometime during the recent cold spell a chunk of the prairie arroyo wall collapsed. Just before the temperatures fell below zero, there had been a little snow - not much, but apparently enough to freeze in the ground and serve as a wedge.

The same area was disturbed several times last year: once in April after several weeks of alternating rain and snow, then again in late December after our first, and only, real snowfall of the winter.

I suppose it’s not unusual for the soft sides of a bank to collapse, but it’s unexpected because I’ve grown accustomed to thinking of arroyos as static. I know, of course, that rocks change, but over millennia. Continental plates only move about 3 centimeters a year, less than an inch and a half. I simply don’t expect to see alternations in the structural landscape when there are no cataclysmic events, no volcanic eruptions, no earthquakes, no storms, not even any sharply contrasting seasons.

The part of the arroyo I walk is actually a dry, sandy stretch that parallels a fault. Up river, one feeder crosses the fault at the point where that branch meets two others that run from another fault in the Miocene uplands formed before the Rio Grande rift opened during the Pliocene. Below, the arroyo meets another arroyo, the narrow one, in the bottom lands, then flows into the Rio Grande.

The taller walls reveal alternating layers of sandy loam and gravel. The thicker slabs are silica enriched by clay. The thinner layers are silicon dioxide in the form of milky quartz and smaller amounts of granite. Both probably came from the Precambrian rock of the Sangre de Cristo, the one less weathered than the other. Quartz is one of the rocks least likely to age quickly.

Down river from where I enter the arroyo the left bank is steeper, perhaps from harder formations. At one place a folded ridge has been exposed. The land has eroded back a little along that ridge to create a second bottom above the tougher lower strata. The right bank is shallower and spreading.

The floor divides into five sections as the water, when it flows, forks around a central island where chamisa has stabilized the soil. On the soft side, between the water path and the wall, more plants grow, while only gravel and sand exist on the hard side.

Up river, it’s the right bank that’s steeper and the left that’s soft. The floor’s not divided, but again the vegetation is limited to the softer side.

Gravel spills from the opened layers whenever wind or rain dislodge it. Then the rock fragments are carried into the main flow of the arroyo where they skim the surface, marking the borders of the water paths, until they’re pushed into the soil by animals or moved farther along. Whatever actual rocks there are, usually no larger than a hand, also relodge along the water edge.

Last fall, after the summer rains, the floor near the downriver steep bank was glazed by glittering flakes of quartz that probably had floated on the surface of the water that carried away the pebbles, then dropped with the water level. The minute rockiness may be why the plants that live in the sandy arroyo don’t take root there, only Russian thistles and clammy weed.

The actual water channels are smooth like frosting when they’re wet, but molded by wind when the moisture evaporates. Some times, I’ll see no footprints in the sand, only ripples in closely grained arcs or wider, deeper partial chevrons. Other times, I can identify my own shoe prints from the week before.

The sections of the upriver steep wall that fell a few weeks ago are a bit like adobe, cakes of mud and stone bound by sticky clay. With time, the wind and rain will strip them, layer by layer, but the process may not be perceptible. The earlier collapsed section was only smoothed by last summer’s rain, not visibly shrunken.

The arroyo may not change as often as the Mississippi, but it lives at its own pace. In the 1920's, D. H. Lawrence wrote about the local landscape that it “lived, and lived as the world of the gods, unsullied and unconcerned. The great circling landscape lived its own life, sumptuous and uncaring. Man did not exist for it.”


Sangre de Cristo uplift

Miocene: 24.6 to 5.1 million years ago

Pliocene: 5.1 to 2 million years ago

Koning, Daniel J. “Preliminary Geologic Map of the Española 7.5-minute Quadrangle,” New Mexico Bureau of Geology, May 2002.

Lawrence, D. H. “St. Mawr,” 1925; the last part was set at his cabin outside Taos provided by Mabel Dodge Luhan.

Photograph: Arroyo, 19 February 2011. The section in front came down in the past three weeks; the section in back fell last April. A Russian thistle and a clammy weed are all that grew there last summer.

Sunday, February 20, 2011

Strapleaf Aster

What’s happening: New leaves on golden spur columbine; Russian olive, juniper and pyracantha berries persist.

What’s still green: Moss, evergreen, yucca, grape hyacinth, Jupiter’s beard, phacelia, pink evening primrose, broom senecio leaves; some grasses.

What’s grey, blue-grey or grey-green: Piñon, four-winged salt bush, yellow alyssum and winterfat leaves.

What’s red/turning red: Cholla, Madonna lily, small-leaved soapwort, beardstongue, yellow evening primrose, creeping mahonia leaves; rose and young tamarix stems.

What’s yellow/turning yellow: Globe and weeping willow branches.

What’s blooming inside: Zonal geraniums on enclosed porch; aptenia in house.

Animal sightings: A mouse came into the house in December when it was cold, but nothing invaded during the past cold spell.

Weather: Clouds all week at daybreak, winds yesterday; last snow 2/4/11; 10:30 hours of daylight today.

Weekly update: When I was a child in the 1950's, I was told composites were the youngest plant family, with the implication that everything had been formed.

Much of the early evidence for evolution had come from fossils laying in chronologically created rock strata. Plant families were seen as life forms that had emerged in particular past climates, the evergreens in the Carboniferous, the ferns in the Triassic, the grasses in the Oligocene. Each was thought to have flourished in its time, with only the most adaptable surviving the subsequent changes in environment.

Composites may have diverged in the Eocene, some 36 to 42 million years ago, but they have survived the tropical Eocene, the dry Oligocene, and the frozen Pleistocene to become the ones most actively adapting to the geobotanical present.

Some argue the reason the family has proliferated is its reproductive strategy matches modern conditions. Instead of a single flower or cluster, numerous small individual florets are held in clumps in a single receptacle, often with the large, outer ray flowers serving no other purpose that attracting insects to the central disk flowers. The seeds are dispersed by wind-driven parachutes.

Since I was a child, botanists have renamed the family the Asteraceae, and turned from fossils to DNA for evidence. They’ve exchanged the absolute "the" and superlative "est" for the safer "a" and "er" as they’ve come to recognize evolution is not just history.

Strapleafed spiny asters have traditional composite flowers, with a single ring of pollen producing rays surrounding yellow, bisexual disks. The long, narrow rays open mid-morning from early or mid June to early November and close each afternoon.

The perennials range from the prairie provinces of Canada to the silver producing states of México. Within that wide belt of plains and dry grasslands, the four pairs of chromosomes are permutating with clear patterns of selection appearing only in areas where populations have become isolated. In a few areas, the number of chromosomes has doubled to 16.

Whenever the separation is destroyed, subspecies begin interbreeding with other populations. Plants in the nodes have taken many forms, which in turn has led to at least ten generic names. The areas between the clearly formed species are filled with gradations that have led to the current preferred term, the Xanthisma spinulosum complex.

In our area the woody stems of the spinulosum subspecies branch almost immediately, to send radiating stems out six or eight inches along the ground before they curve up to hold single, terminal flower heads. When they first emerge, the alternate leaves resemble herringbone evergreens with sharp points.

As the stems elongate, the distance between the leaves expands, while the leaves lengthen with short lobes along central midribs that give them the name tansy aster. Up close, the leaves are bright green, but from a distance appear gray from fine hairs.

Down the Rio Grande in south Texas, the austrotexanum subspecies has an erect, unbranched habit with less deeply incised leaves and no glandular hairs. To the west in Arizona, the gooddingii subspecies has shiny leaves, tall, erect stems, and larger flowers.

Sleepy daisies seem to be particularly sensitive to variations in environment. At the Sevilleta National Wildlife Refuge north of Socorro, the plants prefer the black grama steppes to the blue grama grasslands. The first have rockier, coarser soils than the second, and tend to favor plants like these with long taproots.

During the 1930's, drought along the Missouri River in Iowa, Nebraska and Kansas killed many of the grasses and forbs. Strapleaf asters were one of the few not only able to survive in the drier western areas, but to spread east to colonize newly barren areas when the high winds of the period transported their yellowish-brown seed vessels with the loosened soil.

The plants are often seen in disturbed or open areas: they were first collected by Lewis and Clark on September 15, 1804, the day they passed the mouth of the White River in South Dakota. However, it may not be the tiny seeds need disturbed soil to germinate so much as the plants disappear when competition develops.

They grew in my yard between 1997 and 2002, but never in the same place. Then, a single plant bloomed for two years under the black locust, before disappearing. With the changing population of grasses, they behaved more like annuals than perennials.

Last summer I noticed them in the prairie growing in bare ground left by four-wheeled all terrain vehicles about five to ten feet away from the drop into the arroyo. They appeared there again this past summer.

The Sevilleta research team believes one reason non-grasses like strapleaf asters can coexist with black grama, but not with blue, is that the first begins growth later in the season after the plants have developed, while blue grama emerges earlier and competes with forbs for resources.

Here the pointed yellow rays seem particular well adapted to the cold: both years they continued to appear after morning temperatures had fallen below freezing. Soon after temperatures reached 20 degrees last November, the roots produced new basal growth. After the snow and zero degree cold of late December, those leaves turned dark green and may have died. However, new basal growth has appeared on a few, below the bare woody stems from last season.

Botanists have come to recognize new species result from mutations and genetic experimentation by nature, and that, over time, those species begin to solidify through continued genetic selection. What they’ve found with strapleaf asters is a species that is simultaneously proliferating and winnowing in an evolutionary present.

Barkley, Theodore M., Luc Brouillet and John L. Strother "Asteraceae Martinov," on eFloras’ Flora of North America website, summarizes current knowledge on plant family.

Kröel-Dulay, György, Péter Ódor, Debra P.C. Peters and Tamara Hochstrasser. "Distribution of Plant Species at a Biome Transition Zone in New Mexico," Journal of Vegetation Science 15: 531-538, 2004; identifies Machaeranthera pinnatifida.

McDougall, W. B. "Lessons in Botany," National Park Service Region III Quarterly 3:7-10: October 1941, summarizes the received wisdom of my mother’s generation.

Peterson Field Guide. Southwestern and Texas Wildflowers, by Theodore F. Niehaus with illustrations by Charles L. Ripper and Virginia Savage; uses the term strapleaf spine aster for Machaeranthera spinulosa.

Turner, B. L. "Xanthisma spinulosum var. austrotexanum (Asteraceae: Astereae), An Endemic of Southernmost Texas," Phytologia 89:349-352:2007.

_____ and Guy L. Nesom. "Taxonomic Review of the Xanthisma spinulosum Complex (Asteraceae: Astereae)," Phytologia 89:371-389:2007.

Weaver, J. E. and F. W. Albertson. "Deterioration of Grassland From Stability to Denudation with Decrease in Soil Moisture," Botanical Gazette 101:598-624:1940; identifies
Sideranthus spinulosus.

Photograph: Young leaves, some probably killed by cold, at base of prairie strapleaf aster with seed (achene), 13 February 2011.

Sunday, February 13, 2011

White Bird of Paradise

What’s happening: Russian olive, juniper and pyracantha berries persist.

What’s still green: Evergreens, yuccas, grape hyacinth, Jupiter’s beard, broom senecio leaves; some grasses.

What’s grey, blue-grey or grey-green: Piñon, four-winged salt bush and winterfat leaves; piñon have been dropping leaves, leaving bare grey stems that make the trees look frosted from a distance.

What’s red/turning red: Cholla leaves, Madonna lily, small-leaved soapwort, beardstongue, creeping mahonia leaves; rose stems.

What’s yellow/turning yellow: Globe and weeping willow branches.

What’s blooming inside: Plants have not moved back to their porch yet, but zonal geraniums are still blooming.

Animal sightings: Flock of large birds flying south Friday morning; small birds out here around noon.

Weather: Morning temperatures are no longer below zero, but are still cold; last snow 2/4/11; 10:11 hours of daylight today.

Weekly update: As winter progresses, the dry air between the storms draws water from plants, dead and alive. At first, the color in pigments intensifies, then, as the season passes, the dead matter blanches.

Cary Pirone was fascinated by seeds of white bird of paradise palms because their feathery caps or arils retain their orange color for decades. Then she discovered why: instead of a plant pigment, they contain one previously found only in animals. Bilirubin develops when red cells break down to produce the yellow found in bruises and jaundice. At that point in its chemical life, it’s insoluble in water, which explains why it persists where water-based plant pigments fade.

Most of us never see those bright seeds. We buy Strelitzia nicolai as a house plant which sometimes produces clusters of white flowers held in dark, boat-shaped bracts. The three white, deeply segmented sepals that give the plant its common name rise above the blue petals that surround the nectary. Two are fused to form a channel for the glucose and fructose, while the shorter, third stands above.

In their native dunes along the South African coast from the eastern cape into Mozambique the Natal wild banana is fertilized by sunbirds who land on the bracts, then walk over the lower petals to get to the nectar. As they move, their feet accidentally pick up and drop pollen. Barbets and starlings eat the fruit and spread the seeds.

Less usefully, vervet and samango monkeys eat the flowers, as do blue duikers and bush babies. Insects visit, but don’t pollinate, while bats and frogs live under their protection and predatory mosquitoes and some fungi live in the joints between the leaves and the woody stems.

If we buy the plants for color, it’s more likely for the green of the great oar-shaped leaves which provide a screen against the desolation of winter.

Writers at the PlantCare website believe the plant’s popularity can be traced to a cover of Architectural Digest from the late 1970's. When the photographers needed to fill some empty space, they brought in white birds of paradise for drama. From there the tropical plants spread, first to decorators, then through the mass market to shopping mall atriums.

The owners of the featured apartment never had to worry about the growth habits of the white bird of paradise. The pots were trucked back to the nursery after the shoot.

However, those who imitated the cover soon discovered the plants can quickly outgrow a normal home. In Africa, where they can receive 40 to 50" of rain a year, the tree Xhosa speakers call Ikhamanga and Zulu call Igceba can grow 40' high. Single clumps can reach 13' wide. When nurseries sell them in this country, they often put two in a pot to give the illusion of fullness.

When I took my current job, the boss’s wife had sent hers to the office where its leaves got in everyone’s way. The foreman pushed it far into a corner, then tethered it to the wall. Whenever the leaf margins split, the office manager hacked it with a knife. It got little water because the flimsy plastic saucer underneath had cracked. They succeeded in killing one of the clumps, but the other survived with a few leaves.

A few months ago we moved into a new office. I had someone buy a larger, stronger saucer and the boss dictated it would be given the window. It spread 60". The tallest leaf reached 76", while the largest leaf blade was 38" long.

When I came in the following Monday, there was a second pot with two more plants. One of my boss’s friends was closing his decorators’ showroom, and the thing had to go somewhere. Its arching stems spread 80", wider than the 6' window, and brushed desks on both sides.

We call these great leaves, so unlike our native vegetation, bananas or palms. In fact, as might be expected of a bird pollinated, animal pigmented plant, they’re members of a small family, Strelitziaceae, with only one species, Phenkospermum guyannense, found outside Africa. They emerged 49 to 55 million years ago when jungles dominated the Earth and color never faded.

Notes: A blue duiker is a small antelope; a bushbaby is a small nocturnal primate.

Frost, S. K. and P. G. H. Frost. "Sunbird Pollination of Strelitzia nicolai," Oecologia 49:379–384:1981.

Letsela, Moeketsi. "Strelitzia nicolai Regel & Koern.," Plantzafrica website, 2002, with additions by Yvonne Reynolds.

Muspratt, J. "The Bionomics of an African Megarhinus (Dipt., Culicidae) and Its Possible Use in Biological Control," Bulletin of Entomological Research 42: 355-370:1951.

Nichols, Geoff. Down to Earth: Gardening with Indigenous Shrubs, 2002.

Pirone, Cary L. Bilirubin: an Animal Pigment in the Zingiberlaes and Diverse Angiopserm Orders, 2010. "White Bird of Paradise - Strelitzia nicolai," available on-line.

Photograph: White birds of paradise, 9 February 2011. The one in front is from the designer showroom; the one in back from a decorator’s house.

Sunday, February 06, 2011


What’s happening: We won’t know until spring how much has been killed by these bitter temperatures and dry ground; Russian olives, juniper and pyracantha berries persist.

What’s still green: A thin layer of snow covers most things; evergreens, yuccas, some grasses show.

What’s grey, blue-grey or grey-green: Piñon, four-winged salt bush and winterfat leaves.

What’s red/turning red: Cholla leaves; rose stems, although they’ve been covered with icicles since Thursday.

What’s yellow/turning yellow: Globe and weeping willow branches.

What’s blooming inside: When we lost our heat Thursday morning, I brought everything into the house where temperatures fall to the 40's, rather than the 20's.

Animal sightings: Rabbit tracks in snow when I left for work mid-morning Thursday.

Weather: The temperature fell to -12 Thursday morning, the lowest I ever remember, with only the slightest snow cover; last snow 2/5/11; 9:53 hours of daylight today.

Weekly update: This is the time of year when the most noxious weeds find ways to make human intruders plant their seeds. When I came in Wednesday morning from clearing snow off a thermometer that read 4 degrees, I had a sandbur in my heavy wool sock. It must have been hiding in my rubbers since I last wore them in December.

While I won’t believe it was lurking in the snow, I can believe the sandbur represents one of nature’s most hostile responses to changing environmental conditions.

The Cenchrus genus of grass probably emerged in tropical east Africa. Amelia Chemisquy’s team believes one of its ancestors was the parent of either Pennisetum ramosum, found today in tropical Africa, or Pennisetum orientale, which ranges from northern Africa through the Arabian peninsula into the Caucasus and Himalayas. The other possible parent was the progenitor of Pennisetum setaceum, which grows from tropical Africa north to the Mediterranean littoral that spreads from the Maghreb to the Levant.

Cenchrus longispinus probably developed in North America where it ranged from the Continental Divide to the Appalachians in 1971. Early in the twentieth century, Elmer Wooten and Paul Standley called it one of "the most pernicious weeds" in New Mexico, common in sandy soil at lower elevations throughout the state. Tewa speakers called it Ta nwæ’ig or thorny grass; Spanish speakers called it roseta.

This particular species has become an annual, no longer dependent on warm temperatures for survival. While the seeds may only last about three years, their germination rates are high. J. D. Twentyman found over 96% of those that managed to be buried, germinated within 2 years.

More important, he discovered the burs hold two types of seeds. The ones in the upper spikelet germinate within a year. The lower ones go dormant, and emerge more slowly. They’re programmed to not germinate when exposed to light or unfavorable high or low temperatures.

Beginning in May, the seedlings, which resemble barnyard grass, emerge directly from the bur. Various experts advise people they can confirm their identity by poking around the roots for the burs. This seems silly for two reasons: if they are sandburs, you hurt your finger; if they’re not, you harm a grass you might like to encourage in its place.

I’ve learned the leaves emerge in a V on opposite sides of a center, much like iris leaves. At that stage, the plant is flat to the touch. The more desirable grasses tend to be rounded. Still when you pull them, the underlying bur doesn't come out, but stays in the soil with that slow germinating seed.

Soon after, the leaves start to grow flat in a circle and resemble crabgrass. In July, zig-zagging stalks emerge from the center with bright green flower receptacles that already bear sharp spines. Inside are two minute flowers: the upper one is fertile with two stigmas, the other sterile or male. Flowers continue to appear as the stalk elongates, so the lower burs already hold viable seed while the top is still blooming.

Removing the plants at this time is much trickier than in June. I reach under the leaves and pull the fibrous roots from the soil, then try to carry the flat, round disk of a plant so no part can touch me. When I drop it in a plastic trash bag, I tell myself to remember it’s there so I won’t put something in later and reach down to compact the contents.

The prickles on the oval burs are formed from fused aborted branches on the flowering head. The lower spines are shorter that those above, and point downward. They all attach like velcro.

The only way to remove them is to use your nails and get beneath them so as few spines as possible find your flesh. It’s surprising how quickly you learn to remember the hidden contents of a trash bag.

As the plant completes its annual cycle, the burs harden and fall from the stems. With a killing frost, both the burs and remaining leaves fade to a whitened sand that emphasizes the ridges in the leaves and the sharp spines. By the following spring, the burs are dirty brown. The only ways they can be removed from the surface then is with a trowel or, less happily, a sleeve or pant leg.

During the fall and winter, the burs prevent most animals from eating the one to three seeds within. However, mice are more cunning. Around Pinckney, Michigan, prairie deer mice eat the seeds, while sandbur seeds are collected by plains pocket mice in Minnesota and hispid pocket mice in Oklahoma.

Longspined sandburs can pioneer seemingly barren soil and attach themselves to the animals who may be responsible for the devastation. In the past, I suspect they used the large mammals, then the buffalo to migrate and reclaim disturbed areas. More recently, they have followed sheep and men. They particularly like to colonize abandoned farm lands.

The seeds also punish those sloppy in their harvesting techniques. Wooten and Standley said the burs were particularly common then in alfalfa fields, suggesting contaminated seed. They migrate to Australia in corn exported from this country, then make handling wool dangerous.

Sandburs don’t much like competition - they need the wind to bury and fertilize them. Eventually they will die out where other plants are allowed to take over. However, I suspect even then the impotent burs will persist to attack anyone who wants to redisturb the ground, a knightly protector even in death.

Notes:Australia. Department of Agriculture, Fisheries and Forestry. "Weed Risk Analysis of a Proposed Importation of Bulk Maize (Zea mays) from the USA," March 1999.

Blair, L. F. "Faunal Relationships and Geographic Distribution of Mammals in Oklahoma,"
The American Midland Naturalist 22:85-133:1939.

Chemisquy, M. Amelia, Liliana M. Giussani, María A. Scataglini, Elizabeth A. Kellogg and Osvaldo Morrone. "Phylogenetic Studies Favour the Unification of Pennisetum, Cenchrus and Odontelytrum (Poaceae): A Combined Nuclear, Plastid and Morphological Analysis, and Nomenclatural Combinations in Cenchrus," Annals of Botany 106: 107-130:2010.

Curtin, Leonora Scott Muse. Healing Herbs of the Upper Rio Grande, 1947, republished 1997, with revisions by Michael Moore.

Hibbard, E. A. and J. R, Beer. "The Plains Pocket Mouse in Minnesota," Flicker 23:89-94:1960.

Howard, Walter E. and Francis C. Evans. "Seeds Stored by Prairie Deer Mice," Journal of Mammalogy 42:260-263:1961.

Iowa State University. Department of Ecology, Evolution, and Organismal Biology. "Sandbur (Longspine Sandbur)," Grasses of Iowa website.

Robbins, William Wilfred, John Peabody Harrington, and Barbara Friere-Marreco. Ethnobotany of the Tewa Indians, 1916.

Twentyman, J. D. "Environmental Control of Dormancy and Germination in the Seeds of Cenchrus longispinus (Hack.) Fern.," Weed Research 14:1–11:1974.

United States Department of Agriculture. Agricultural Research Service. Selected Weeds of the United States, 1970, reprinted by Dover as Common Weeds of the United States, 1971.

_____. _____. Germplasm Resources Information Network. Distributions for Pennisetum species available on line.

Wooten, Elmer Otis and Paul Carpenter Standley. Flora of New Mexico, 1915.

Photograph: Sandbur laying beside the road, 30 January 2011; burs are hidden among the leaves.