Not ferocious or fearsome

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After the last post, with its photograph of a spider devouring a damselfly, here’s a milder picture. Yes, there’s still a spider, but only a tiny one, no more than an eighth of an inch long, and doing no harm to any other creature. If you’d like a closer look at the miniature spider, you can click the icon below.

Many of you recognize the plant as a Texas thistle, Cirsium texanum, with a flower head that is fading and about to start decomposing. Doesn’t the bundle of purple florets remind you of an old-fashioned shaving brush? The conspicuous pappus snagged on the right side of the flower head had apparently blown over from another Texas thistle in a more advanced stage of decomposition.

I took this picture on June 8 on a stretch of Bluegrass Dr. that has remained in a natural state even though houses line most of the road. This portion of it slopes down steeply enough that the immediately adjacent land there is probably (and thankfully) unsuitable for building. That has made the fringes of land on both sides of the road suitable for me to keep taking nature pictures over the past few years.

© 2012 Steven Schwartzman

Three orbs, three colors

One orb, the largest of the three, is yellow; it belongs to a spider. The other two orbs, equal in size to each other but smaller than that of the spider, are azure; they’re the characteristically bulging eyes on opposite sides of a damselfly’s head. The third color is red, the red of a turk’s cap flower, Malvaviscus arboreus, whose out-of-focus presence in the background frames the drama of the yellow and blue orbs, in which the damselfly has succumbed to the spider. Though these predatory scenes are common in nature, some of you understandably find them unpleasant, so I’ve shrunk the picture to the icon in the next line. Click it if you’d like to see the dramatic details, pass it by if you’d prefer not to.

I took this picture on June 16 at Hornsby Bend in southeast Austin.

© 2012 Steven Schwartzman

The tetragon gives way to the cone

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After the fragrance of nerve-ray fades, after its seeds have matured and fallen to the ground, what remains is often a conical core with a stiff fringe surrounding its base. At this stage Tetragonotheca texana resembles some of its neighboring relatives in the sunflower family when they’re similarly advanced. And speaking of advancing, this is the fourth and last post in the current miniseries about a species known colloquially not only as nerve-ray but also as square-bud daisy.

For those of you who are interested in photography as a craft, points 1,3 4, and 8 in About My Techniques are relevant to this image.

© 2012 Steven Schwartzman

A double dose of four and nerves

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The last post might have left you wondering how a four-sided bud of Tetragonotheca texana opens into a flower head. The post before that one showed two fully open flower heads stuck together, but you saw only glimpses of green representing the four bracts that had surrounded each developing flower head. Today’s picture should make clear how the bracts separate and fold down as the flower head opens.

If you’re also wondering about the title of this post, the first nerve is the one in nerve-ray, a colloquial name for this wildflower. The other nerve comes from the Tetraneuris linearifolia, or four-nerve daisies, that were in the background and account for the yellow haze across the bottom of the photograph. The two fours are the tetras at the beginning of the genus names Tetragonotheca and Tetraneuris.

© 2012 Steven Schwartzman

A nerve-ray bud

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Yesterday’s post mentioned that nerve-ray, Tetragonotheca texana, is a wildflower whose buds are noticeably four-sided. That’s 100% true, even if today’s picture shows you only 50% of the sides. Each pair of sides meets at an angle and forms a noticeable seam along the juncture. You can see three of those ridges here: the one that follows the line of the flower stalk, and the two that outline the left and right contours of the bud. Behind this bud is a fully open flower head of the same species.

Date: April 9.  Place: the right-of-way beneath the power lines that run across a part of my Great Hills neighborhood in Austin.

Posted on this date last year, in the middle of the drought, when Austin had already had 43 days on which the temperature reached at least 100°: a photograph showing how flowerful the spring of 2010 had been.

© 2012 Steven Schwartzman

A tetragon is a quadrilateral

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There goes the math teacher again: two fancy generic names for a four-sided figure are indeed quadrilateral and, less commonly, tetragon. I bring that up only to introduce Tetragonotheca texana, a native wildflower whose buds are noticeably four-sided. Most daisy-type flowers in the sunflower family seem scentless, at least to people, but this one has a sweet fragrance, and I almost always make myself stop and smell not the roses but the nerve-ray flowers, which is one colloquial name for them; another is square-bud daisy.

I found these two nerve-ray flower heads temporarily stuck together on April 9 on the right-of-way beneath the heavy-duty power lines that cross a part of my Great Hills neighborhood in northwest Austin. The last time you saw some stuck-together flowers in these pages was about five weeks ago, when the species in contact were a Texas thistle and some prairie parsley.

In the United States this species grows only in Texas, as the species name texana truthfully tells us, and as we can see on the USDA map.

© 2012 Steven Schwartzman

Drama in black, chartreuse, pink and yellow

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On July 25, 2011, a year and a day ago, I went to the prairie restoration at Austin’s old Mueller Airport. At one point during a walk around the pond there, I sat down to photograph some flowers of sensitive briar, Mimosa roemeriana. Briars these plants surely are, with recurved prickles that have a knack for embedding themselves in the skin of people who handle them incautiously. And it isn’t only people’s skin that’s sensitive: touch the compound leaves of one of these low-growing plants, and watch the little leaflets fold shut within seconds.

But a drama other than the closing of leaflets caught my attention once I’d sat down. On the underside of this flower globe I noticed two tiny chartreuse caterpillars, and I saw that a couple of ants had noticed them, too. The ants ran up and down, often treading on and continuing over the little caterpillars, occasionally grabbing at them as if trying to pull them away. Perhaps the ants looked forward to a meal, or perhaps they were defending their territory. I don’t know enough about ant behavior to say, and although I watched and took pictures for a while, nothing conclusive happened. Eventually, say anticlimactically if you wish, I continued on my way.

UPDATE: See the explanatory comment below by Spider Joe Lapp.

© 2012 Steven Schwartzman

Rain-lily detail

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Yesterday’s post showed a rain-lily, Cooperia pedunculata, that recent rains had caused to flower on July 13th. Rain-lilies last only a few days, and no sooner is one of these flowers fully open than its pristine white begins to take on a pink tinge, as you see in this close view; from here the coloration will quickly darken and signal the flower’s demise. Tinge aside, I’ll add that the tepal looks to me as if it were made of snow or ice.

© 2012 Steven Schwartzman

A rain-called lily called rain-lily

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In addition to the Habranthus tubispathus of the the last two posts, another small lily called forth on July 13 by the rain, and even named for that behavior, is the rain-lily, Cooperia pedunculata. As opposed to the copper lily, its flowers are white rather than yellow, and this one was blowing a bit in the breeze, as you can see from the blurred tips of a few of its tepals. (You’re familiar with petals, and you may be aware that as they develop they’re surrounded by outer segments called sepals; when a species has petals and sepals that are practically identical, botanists refer to them both as tepals.)

I took this photograph in the same place as the last two pictures, the right-of way beneath the large power lines crossing a portion of my Great Hills section of northwestern Austin.

© 2012 Steven Schwartzman

Copper lily in an earlier phase

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In the last post you saw a copper lily, Habranthus tubispathus, that with a few others of its kind had been called forth on July 13 by the consecutive rainy days we’d been having in Austin (and continued to have for several more). Perhaps half a dozen already open little flowers were scattered about, but there were several times as many buds rising from the ground. You see one of them here, alongside part of a taller stalk.

© 2012 Steven Schwartzman