Portraits of Wildflowers

Perspectives on Nature Photography

Not crop circles

with 29 comments

Ruellia nudiflora Flower with Circles 8033

While you’ve probably all heard about the hoaxes called crop circles, here are some strange little circles that I doubt any hoaxer would have taken the time to create. These tiny pale rings are in the petals of a wild petunia*, Ruellia nudiflora, a common wildflower that thrives in Austin’s summer heat. I don’t remember ever seen anything like this, so if anyone has an explanation for these marks, please speak up. One thing I’m sure didn’t create them is miniature alien spacecraft, but if any of you can parlay that into a fad for Petal Circles, I want my share of the royalties.

I took this picture on July 18th during the same jaunt through Great Hills Park that brought you a picture of a turk’s cap flower.


* Don’t be fooled by the common name. The wild petunia that’s native in Texas belongs to the acanthus family, while garden petunias come from South America and are in the nightshade family.

© 2014 Steven Schwartzman

Written by Steve Schwartzman

September 19, 2014 at 5:13 AM

29 Responses

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  1. minerals left after water evaporation.

    Andrée Reno Sanborn

    September 19, 2014 at 5:18 AM

  2. Since you use the word parlay http://www.urbandictionary.com/define.php?term=parlay and it is International Talk Like a Pirate Day, may I conjecture some utter nonsense; bored fairy pirates drawing with their swords. Otherwise I have no idea. But the rings don’t detract from the beauty of the wild petunia.


    September 19, 2014 at 5:44 AM

    • Perhaps you’ll popularize pirate petunias.

      Urban Dictionary has some colorful and fanciful definitions, but you get what you get. The proposer of the second entry for parlay has confused the word with parley.

      Steve Schwartzman

      September 19, 2014 at 6:21 AM

      • As long as no one pirates your Petal Circles idea, all will be well.


        September 19, 2014 at 6:40 AM

  3. Too uniform to be mineral deposits. I think Gallivanta was perhaps close when involking Fairies. I would suggest that this might be evidence of fungal infection … and that what we’re seeing are Fairy Rings (http://en.wikipedia.org/wiki/Fairy_ring), but on a small scale? Each ring is formed by a number of germinating spores which were, themselves, generated from a single individual at the center of each ring. Just a guess. D

    Pairodox Farm

    September 19, 2014 at 6:02 AM

  4. My first thought was water droplets. Most of the time, raindrops don’t cause any problem with my varnish, but now and then they bring “something” from the air with them, and leave perimeter rings that can’t be wiped off like simple mineral deposits. It’s almost as though the drops etch the varnish, and serious rubbing, or even sanding, is the only answer, even if the drops haven’t completely evaporated. In short: acid rain drops.

    My second thought was fairy rings. They’re all over right now, bigger and more complete than I’ve ever seen. And those brought to mind ringworm, another fungal infection that presents in just this way. I think I’d take fungal infection over evaporated water as an answer.

    As for the flower itself, I was surprised to see it called wild petunia. I’ve always thought of it as Katie Ruellia, or Mexican Petunia. But now I see that the Mexican petunia is Ruellia brittoniana, different from our native wild petunia.


    September 19, 2014 at 7:17 AM

    • I looked up pictures of ringworm on people’s skin. I see some of them are rather circular, though not quite as regular as the rings on this flower—or maybe the rings on the flower seem more regular than they are because they’re so small. Your suggestion of a fungus seconds D’s (Pairodox), and that certainly seems plausible. I’m wondering why I hadn’t seen this phenomenon in a flower, but then there are so many things I haven’t seen, as well as things I’ve seen but not noticed.

      Katie Ruellia sounds like the name of a person.

      I get the impression you’ve read p. 229 in the Tveten book.

      Steve Schwartzman

      September 19, 2014 at 7:53 AM

      • I hadn’t read Tveten, but now I have. I’ve never heard the low-growing, bushy version called “Kate’s compact.” Around here, it’s known as dwarf Ruellia, and it’s a landscaper’s favorite. The tall version of both species can spit their seeds a good distance, much to the chagrin of a hill country friend who thought she’d like to transplant some, and now can’t control the stuff.


        September 19, 2014 at 8:10 AM

  5. Didn’t know that there is a wild petunia. It’s lovely, especially with the added mysterious rings. If there was something in the water that leaves a mineral deposit, wouldn’t it affect the entire surface?


    September 19, 2014 at 7:55 AM

    • Yes, Virginia, there is a wild petunia (even if it isn’t actually a petunia). Wild petunia flowers are still common in Austin now, two months after I took the picture in today’s post.

      My understanding is that the hypothesis of mineral rings assumed there had been drops of liquid that evaporated, leaving rings only where the drops had been.

      Steve Schwartzman

      September 19, 2014 at 8:10 AM

  6. Lens effect of water drops… The Sun was probably at the right angle to do a little burning…

    Joe Dorn

    September 19, 2014 at 8:11 AM

    • I thought about a lens effect, but I’m pretty sure that’s not what’s at work here because other pictures of the same flower taken at other angles show the circles in the same places on the petals.

      Steve Schwartzman

      September 19, 2014 at 1:53 PM

      • Notice also that there are some raindrops on the petals, but they’re not producing any of the little circles in the photograph.

        Steve Schwartzman

        September 19, 2014 at 1:57 PM

  7. I wonder if it’s a parasite that affected it when the petals were still closed? It looks like the circles could overlap when furled. Do you mind if I send the image to the Royal Horticultural Society to see if they’ve seen this before?

    Sarah Longes - Mirador Design

    September 19, 2014 at 11:24 AM

  8. Stunning shot. I love the colour. I have never seen circles like these before. 😀

    Raewyn's Photos

    September 19, 2014 at 3:17 PM

    • These wild petunias are a rich source of purple throughout the hot Texas summer.
      The little circles are not a normal part of out hot summers—at least I don’t think so.

      Steve Schwartzman

      September 19, 2014 at 4:34 PM

  9. I don’t have an answer, but I have a clue. The word is “halos.” There are fungal halos, and chlorotic halos, and halos on petunias that apparently are caused by a virus. They seem to be most common on leaves. It seems the infection (or whatever) takes hold at a certain point, and the halo is formed as the disease moves outward as a ring. My guess is that’s what’s happened here.


    September 19, 2014 at 5:47 PM

  10. What a beautiful post to end this Friday.

    Charlie@Seattle Trekker

    September 19, 2014 at 11:37 PM

    • And to end it with a mystery, as well as a reminder of the song “May the circle be unbroken.”

      Steve Schwartzman

      September 20, 2014 at 6:43 AM

  11. I had the same thought as Andrée and also follow what David is saying about fairy rings. But most of the fairy rings I have seen are not circular…at least not a regular circle. I also like Linda’s research results. I think we may have to sacrifice a petal or two to science.

    Steve Gingold

    September 20, 2014 at 6:30 PM

    • Would that I could get in my time machine to go back and pluck one of those petals for science.

      Steve Schwartzman

      September 20, 2014 at 9:29 PM

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