Portraits of Wildflowers

Perspectives on Nature Photography

A tetragon is a quadrilateral

with 16 comments

Click for greater clarity.

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

Written by Steve Schwartzman

July 27, 2012 at 6:03 AM

16 Responses

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  1. In Liberia, it’s the custom to welcome a visitor or new resident with a flower-decorated palm arch over the path leading to the front door. I haven’t thought of that in ages, but this beautiful arch, somewhat enlarged, would have done beautifully. Lovely capture.


    July 27, 2012 at 8:16 AM

    • It would take a Lilliputian to walk under this arch. I’m glad it reminded you of a happy custom in Liberia.

      Steve Schwartzman

      July 27, 2012 at 9:13 AM

  2. Man, I dig this flower’s squareness! 😉
    ~ L


    July 27, 2012 at 2:41 PM

  3. Lovely image!


    July 27, 2012 at 11:34 PM

    • Thanks, Terry. I had thought about your blog a few minutes before I found this comment. I must be psychic.

      Steve Schwartzman

      July 28, 2012 at 5:19 AM

  4. […] 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. […]

  5. Flower to the second power!

    Sheila T Illustrated

    July 28, 2012 at 7:12 AM

  6. I love that you photographed these while still joined rather than impulsively ‘putting them right’ first. It is a creative and admiring eye that saw to create this image.

    Cindy Kilpatrick

    July 28, 2012 at 8:26 PM

    • Thanks, Cindy. I’m always on the lookout for something out of the ordinary. I do a lot of looking, and at times I find something.

      Steve Schwartzman

      July 28, 2012 at 10:49 PM

  7. […] 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 […]

  8. Love this composition!!!


    August 1, 2012 at 10:24 AM

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