Portraits of Wildflowers

Perspectives on Nature Photography

Another Mexican hat anomaly

with 12 comments

Eight days ago you saw a Mexican hat (Ratibida columnifera) flower head that strangely had four columns instead of the single one that’s the norm. On May 15th the Mexican hats at the Floral Park Drive entrance to Great Hills Park were going strong, so I walked in to give them a closer look. On one flower head I discovered another anomaly: several ray florets were emerging from a place part-way up the column where only disk florets are supposed to grow. For comparison, check out the normally developing Mexican hat below, with ray florets coming out only at the bottom of the column.




To see some impressive wildlife photographs, check out the work of Dave Newman, a British office manager who takes pictures on his lunch break. Avian mavens among you should be especially interested.


© 2022 Steven Schwartzman




Written by Steve Schwartzman

May 27, 2022 at 4:30 AM

12 Responses

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  1. This year it seems that anomalies are all the rage. Besides the trillium I shared I also found another flower yet to be processed with an abnormal, at least to my understanding, number of its usual contingent of individual flowers per plant. The upper Mexican Hat seems to be ray flowering to the beat of its own drummer.

    Steve Gingold

    May 27, 2022 at 4:51 AM

    • You’ve raised the interesting question of whether anomalies occur at an approximately constant rate or whether their occurrence varies significantly from year to year. The same question could be asked about our noticing of anomalies, apart from their actual occurrence.

      Steve Schwartzman

      May 27, 2022 at 6:09 AM

  2. Interesting discovery, Steve! It raises the question of what is normal and what is not.

    Peter Klopp

    May 27, 2022 at 8:21 AM

  3. I like all your close-up shots of Mexican hats of late. I hope mine come up nice this year. I sprinkled more seeds but it has been very dry.


    May 27, 2022 at 10:56 AM

    • I find Mexican hats lend themselves to abstraction, which I’ve been working on for some time now. Despite Austin’s drought (till finally some recent rain), the Mexican hats came up as profusely as in any non-drought year.

      Steve Schwartzman

      May 27, 2022 at 11:27 AM

  4. Many of the anomalies you find are interesting, and some are attractive, but this one seems just weird to me. I noticed the indentation above the odd protrusions. I wonder if the flower head was affected by ‘something’ in such a way that the energy meant to produce a symmetrical head pushed its way out down below.


    May 28, 2022 at 7:34 AM

    • Two years ago I got this answer about Mexican hat anomalies from U.T. botanist George Yatskievytch:

      “Fasciation in things like Asteraceae heads is a fascinating topic. It can result from several potential causes, including pathogenic viruses and mycoplasmas, insects (whose frass might contain growth hormone-like substances), or environmental conditions. There are lots of really neat examples, especially in Echinacea and Rudbeckia, with a flattening and/or elongation of the receptacle. I had not seen fasciation in Ratibida before, but why not!

      “Replacement of flowers is a bit different process. Each meristematic cell on the receptacle produces a set of cells with the potentiality to become either a ray or disc floret. Regulatory developmental genes in more than one gene family determine the outcome of the differentiation. It is a good thing that humans aren’t built like these flower heads. It would be awkward to have a finger develop in place of a … Never mind, that’s not appropriate.

      “Anyway, this accounts for ‘rayless’ mutants, as well as heads in which part of the disc has become replaced with rays. This includes so-called ‘doubled’ heads in groups like zinnias and dahlias that have extra cycles of rays toward the periphery of the disc, as well as odder mutants with rays appearing in an atypical locations, such as the center of a disc. In some cases, this switch to a different floral morphology is caused by something that disrupts normal development of the head (such as insects or micro-organisms), but in other cases there is a genetic mutation (in which case the plants will tend to pass the mutation to at least part of the next generation). One of the more interesting mutations that I have seen pops up occasionally in Gaillardia, in which the marginal florets have corollas that are enlarged, but are still basically shaped like a disc floret at their tips.

      “The bottom line is that there can be more than one cause, but it always comes down to the expression of regulatory genes during floral development.”

      Steve Schwartzman

      May 28, 2022 at 7:59 AM

      • That’s really interesting — especially the tidbit about frass containing growth-hormone like substances. I need to pull together some of my photos of oddities. Look at the bowl-shape of this sow thistle. I might have other photos that show it better, but it was noticeable enough that I spotted it while driving. I’d forgotten about the flattened Texas dandelion I found at the Broadway cemeteries, too. I knew it wasn’t precisely fasciated, but it sure did look odd.


        May 28, 2022 at 8:25 AM

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