Sunday, September 30, 2007

Muhly Ring Grass

What’s blooming in the area: Roses, Apache plume, silver lace vine, buddleia, honeysuckle, canna, datura, Heavenly Blue morning glory, narrow leaf globemallow, white sweet clover, yellow evening primrose, lamb’s quarter, Russian thistle, pigweed, chamisa, broom snakeweed, winterfat, Tahokia daisy, Maximilian and native sunflowers, áñil del muerto, ragweed, gumweed, wild lettuce, broom senecio, golden, heath and purple asters; catalpa beans, hay cut.

What’s blooming in my garden, looking north: Golden spur columbine, hartwegii, nasturtium, chocolate flower, blanket flower, coreopsis, Mexican hat, black-eyed Susan, yellow cosmos, chrysanthemum.

Looking east: Fashion rose, garlic chives, pinks, rock rose, sweet alyssum, winecup, hollyhock, California poppies, Crackerjack marigolds.
Looking south: Rose of Sharon, rugosa rose, Crimson Rambler morning glory, Sensation cosmos, zinnia.

Looking west: Caryopteris, Russian sage, catmint, leadplant, ladybells, purple ice plant, Monch aster.

Bedding plants: Sweet alyssum, snapdragons, petunia, Dahlberg daisy.

Inside: Aptenia, zonal geranium.

Animal sightings: Quail, gecko, ants, bees.

Weather: Rain Sunday, Friday and yesterday, prairie wet deeper than my shovel; frost on car windows Thursday morning; low hanging, full moon before dark on Wednesday.

Weekly update: We finally got rain last week, and now the habitues of late summer have resumed growing, racing to produce seed before it gets too cold.

The rains began last Monday. Áñil del Muerto germinated last Saturday, and put out its second leaves two days ago. There was sun on Monday and Muhly ring grass showed some green that afternoon, as did the black grama and needle grasses. Downy chess grass sprouted in the drive.

Muhly is one of the grasses that colonizes land denuded by overgrazing. It’s palatable in early spring when it’s growing, but goes dormant in the heat of the summer and turns dry and harsh. When the monsoons appear, it regreens to send up short purple culms with seeds that are also unappetizing.

Not only is it well armed against herbivores, but it also adapts to scarce water. The perennial begins as a small round tuft. Over the years, the tuft turns into an inch or two greyish white wide band that expands outward, leaving an ever widening doughnut opening. When it greens up, it begins on the outer faces, where seeds form. In relatively flat areas, its new growth appears on all sides; on more sloping land ring muhly greens on the downhill or wet side first.

When I see it spread across the top of my south facing slope, I wonder if it prevents or abets erosion by stopping or channeling the flow of water. The recent rains have been able to sink into the ground, instead of rolling downhill. The ring, or its shadow, acts as a small reservoir where other seeds plant themselves and its shallow tenacious, fibrous roots hinder the wind.

The 2" high grass’s life cycle is heavily dependent on rainfall. During the droughts of the past few years, it all but died out, and snakeweed invaded its territory. With last year’s rains, it came back in the area where the needle grass had died, but didn’t try to resettle the area with the broom.

Frederic Clemens believed the order of succession on damaged arid lands was annual grasses, short perennial grasses, bunch grasses with ring muhly, and, finally, the original gramas. Others have since found grasslands rarely get beyond the needle and rice grasses, and that factors like weather and soil influence the progression.

Even if my uphill neighbor hadn’t told me he had worked for the ranch that owned this land before he settled on its perimeter, the mere presence of Muhlenbergia torreyi could have told me. I don’t know if it was cattle or sheep, but the remains of animal chutes near the old road bed don’t look wide enough for full-grown cows.

What I don’t understand is why it only appears on the upward side of my house, and why the lower land and much of the surrounding prairie are predominantly needle grass. I’m guessing there could be differences in the quality of the soil, or that area near the ranch perimeter may have been trampled more and the compacted soils less porous, less receptive to water.

It does appear the grass can’t compete with other vegetation, and that it dies out when either the bunch grasses or the scrub seed themselves. It also doesn’t like being crushed and cracks when it’s stepped on during its dormant phases. It would appear to be the first thing to disappear when humans or animals appear. While it seems common enough, in fact, in this area, its period of existence is limited by both humans and nature.

Clements, Frederic E. Plant Succession and Indicators: A Definitive Edition of Plant Succession and Plant Indicators, 1928, discussed by Debra P. Coffin, William K. Lauenroth and Ingrid C. Burke, "Recovery of Vegetation in a Semiarid Grassland 53 Years after Disturbance," Ecological Applications, 6:538-555:1996.

United States Department of Agriculture, Forrest Service, Range Plant Handbook, 1937, republished by Dover Publications, 1988.

Photograph: Muhly ring grass, 29 September 2007.

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