Sunday, May 15, 2011

Western Goat's Beard

What’s blooming in the area: Snowball, Persian yellow, tea and miniature roses, peony, oriental poppy, Jupiter’s beard, golden spur columbine, moss phlox fading, donkey tail spurge darkening; people set out pepper plants.

Beyond the walls and fences: Fernleaf globemallow, cheese mallow, western stickseed, bractless crypthanka, tansy and tumble mustard, alfilerillo, bindweed, gypsum phacelia, western goat’s beard, native and common dandelions, rice, three awn and cheat grasses; June grass shedding seed; tree of heaven coming back from cold; goat’s head coming up through road paving; buffalo gourd and goldenrod up.

In my yard: Spirea, Siberian pea tree nearly gone, skunkbush, iris, vinca, yellow alyssum peaked, oxalis, small-leaved saponaria, Bath pinks, snow-in-summer, blue flax, pink evening primrose, pink salvia, chocolate flower; buds on privet, catmint, sea pink and baptisia; black locust recovering from cold; butterfly weed, white spurge, calamintha and lead plant emerged; creeping mahonia has new leaves; wind blew petals off tulips early.

Bedding plants: Sweet alyssum, pansy.

Inside: Zonal geranium, aptenia, asparagus fern.

Animal sightings: Hummingbird and small brown birds, gecko, small dark butterfly with orange spots, harvester and small black ants, earth worms.

Weather: Wind relentless as temperatures creep higher; last snow 5/01/11; 15:03 hours of daylight today.

Weekly update: Flowers on western goat’s beard remind me of those imitation crystal snowflakes sold in December to put in the window or on a tree. The thick, clear plastic doesn’t reflect or refract light, nor does it let it pass through. The ornaments are visible simply because they block light.

Tragopogon dubius flowers are concentric rings of long, narrow straps. The outermost are pointed, light-green bracts, usually 13 in number. Inside there’s a shorter row of light yellow, five-pointed petals, sometimes offset from the bracts, sometimes overlapping, that gives them their unique sunburst character.

Each afternoon, the bracts fold, shutting the flowers for the night. The following morning, usually about the time I go to the post office on Saturdays, they reopen facing the sun. While the flowers respond only to light, they don’t have to be directly in the sun to open, only close enough to sense it. I have several growing in back that open a little after nine before the sun actually reaches them.

Each day, the center of the inch and a half wide inflorescence expands. The mound of ray florets - for this composite has no disks - has a central core of still unopened flat yellow envelopes that are narrow at the base and pulled tight at the top. Inside each is a brown tube that leads to a white threadlike ovary and black anthers, which John Hilty says, are pressed against the dark style.

The outer row of unopened petals pulls away from the tip, elongates and opens in the center to form a protective tent around the reproductive organs. Narrow yellow tubes at the tops of the styles lengthen, then branch into lighter colored Y’s to capture the darker yellow pollen spread by insects from this or neighboring plants.

Later, the stigmas darken and fall away, sometimes caught like corn silk when the bracts close and trap the pollen. When the next row of petals begins to swell, the already opened ones are pushed against the previously opened florets and eventually lie against the frame.

When all the florets have opened, the ovaries harden into seeds and the receptacle, that sits on a hollow cone, reflexes. The white hairy sepals surrounding each floret elongate into winged parachutes that form a ball, like that found on the closely related dandelion, only much larger, usually two to three inches across, and tawny.

The outer seeds, the ones formed first, are darker and heavier because they contain more phenolic compounds. When a wind comes, they fall closer to the parent plant than the lighter, younger ones. The larger seeds germinate later and produce larger, taller seedlings.

The waxy leaves are as fustian as the flowers. Many describe them as grass-like, because they’re long and narrow. However, they’re immediately identifiable along my drive, because they don’t look anything at all like the surrounding bunch grasses. They’re darker green, taller, and curve inward into claws. It’s obvious they surround a single stalk and are not so many independent blades rising from a crown.

The basal rosette emerges in late summer when newly ripened seed has fallen and temperatures are still between 59 and 72 degrees. The biennial doesn’t bolt until the root crown expands beyond .11 centimeters, and is most likely to bloom when its about quarter inch across and the plant has undergone some period of coolness.

Although an urn of leaves and its supporting root may store carbohydrates for years before conditions are right for it to flower, a stalk usually rises the following spring. The spaces between the original leaves lengthen into a mop.

At the current stage of many in my yard, the conical bud at the tip of the stem peaks up from the nest of leaves. As it pushes from its skirt, new leaves will open from swollen joints on the stem, each wide at the base, then narrowing into a folded blade like the lower ones.

As the stalk grows, it may branch, with each subordinate stem also pointing upwards. The plant will continue producing terminal heads as long as conditions are favorable. Although they usually peter out by late summer, last year there were flowers until frost in late October.

When they die, the hollow stems harden into inverted wooden umbrellas one to two feet high. The plants that grow in the drive become dangerous to the car and must be removed. Undisturbed plants break away in winter and join the tumbleweeds.

I usually pull them after the monsoons when the ground is throughly wet. The taproot is deep, thick, and strong enough to come out in one piece. When the ground is dry, like it is now, the stem snaps and a white milky sap is released. The only way they can be controlled early in the season is by cutting them before they go to seed.

Even then, western goat’s beard puts up new stalks, sometimes shorter ones, and continues to produce flowers so out of scale with their surroundings they draw attention to themselves. Like the plastic snowflake that doesn’t deliver the promised light, my fascination with the flower shape is deadened by the sheer size and rigidity of its internal and external parts.

Enlargement destroys delicacy when it makes things too visible.

Clements, David R., Mahesh K. Upadhyaya and Shelley J. Bos. “The Biology of Canadian Weeds. 110. Tragopogon dubius Scop., Tragopogon pratensis L., and Tragopogon porrifolius L.," Canadian Journal of Plant Science 79:153-163:1999.

Gross, Katherine L. “Predictions of Fate from Rosette Size in Four "Biennial" Plant Species: Verbascum thapsus, Oenothera biennis, Daucus carota, and Tragopogon dubius,” Oecologia 48: 209-213:1981.

Hilty, John. “Western Goat's Beard,” Illinois Wildflowers website.

Maxwell, Christine D., Alicja Zobel and David Woodfine. “Somatic Polymorphism in the Achenes of Tragopogon dubius,” Canadian Journal of Botany 72:1282-1288:1994.

Photograph: Western goat’s beard, picture taken while plant was still in shade around 10:35 on 8 May 2011 and old enough to have a reduced core but no so old that the outer petals are flattened yet.

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