Portraits of Wildflowers

Perspectives on Nature Photography

Toothed spurge

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Euphorbia dentata 9577

I think the plant making its debut here today is toothed spurge, Euphorbia dentata, a rather inconspicuous native species. I’ve occasionally found it in my back yard, but I photographed this one half a mile away, in Great Hills Park, on October 2. If you sense a vague resemblance to poinsettia—though with white rather than red, and a Texan rather than a Mexican origin—that’s because the two are in the same (and very large) genus. So are the Texas natives fire-on-the-mountain, snow-on-the-mountain, and snow-on-the-prairie.

© 2013 Steven Schwartzman

Written by Steve Schwartzman

October 31, 2013 at 6:02 AM

17 Responses

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  1. Our Spurge is a scourge as far as I am concerned. Some popped up in our garden along the foundation behind our house and we cannot get rid of it. The least hint of remaining root hair yields a bumper crop the following year. It’s great as a roadside groundcover but not in the yard. I realize I’ve made a huge generalization as I have been lax about keying the exact species. As they say-your mileage may vary.

    Steve Gingold

    October 31, 2013 at 6:41 AM

    • I’d urge that you purge that scourge of a spurge from your garden, but I understand your difficulty. The Euphorbiaceae, or spurge family, is an enormous one, so I also can’t fault you for not being sure which species has invaded your land. (Note that in today’s post I said I think the plant is Euphorbia dentata, but I’m not positive.) Just yesterday I photographed two smallish members of the family that I’ll now have to work at identifying. Maybe I’ll succeed and maybe I won’t: my identification “mileage” varies.

      Steve Schwartzman

      October 31, 2013 at 8:10 AM

  2. Beautiful plant and beautiful shot. The white is intriguing. I wonder how this plant is pollinated? I ask because many birds and insects have sensory capacity in the UV and the white highlights against the dark green probably do some pretty interesting stuff in that part of the electromagnetic spectrum. D

    Pairodox Farm

    October 31, 2013 at 6:44 AM

    • At least one source I looked at made an observation like yours, that the white areas at the bases of the upper leaves may help pollinators find the plant’s tiny flowers. Fortunately there are plenty of equally tiny insects that I’ve observed on flowers like these, which therefore seem to have no trouble getting themselves pollinated. Like you, I’ve read that many insects and other animals can see in the infrared and ultraviolet spectra, and I’ve seen photographs taken in those wavelengths that reveal plant patterns that our human eyes can’t see.

      Steve Schwartzman

      October 31, 2013 at 8:17 AM

  3. I’m glad you mentioned poinsettia, because I sensed the resemblance but might not have made the connection myself.

    And my poor mind finally has clicked. When I read Euphorbia, I thought of Snow-on-the-mountain and Snow-on-the-prairie. But dentata was familiar, too. I tracked it down and found it’s used to describe goldeneye – Viguiera dentata. On the USDA site, it’s called toothleaf goldeneye.

    And that was the moment of revelation. Why were two such different plants both described using dentata? I searched for “plant classification” and found this simple entry that describes binominal classification, genus, species, and so on and so forth.

    Honestly. You’d think I’d have figured this out before now. Still, the pleasure of suddenly understanding something far outweighs the embarassment of not understanding.

    And I certainly hope you haven’t suffered from that terrible flooding overnight.


    October 31, 2013 at 6:45 AM

    • For decades I’ve been an advocate of bringing etymology lower down (or at all!) into the school curriculum. I think elementary school teachers would do their students a great service by explaining, for example, that dent- means ‘tooth.’ That’s why a tooth doctor is called a dentist, and why a dentate leaf has little “teeth” on it, and why indentations in the paragraphs on a page are like little white teeth cutting into the text. And of course I’d urge elementary school teachers to explain during science lessons that we classify kinds of living things with two-part names, with the second part usually being a word that tells some characteristic of the species. As you say, better late than never.

      We had rain here (and thunder and lightning) for most of the night. I haven’t looked at the news yet, but I imagine some of the usual low-lying areas got flooded. It’s not raining at the moment, so I may run down and see how Great Hills Park is looking.

      Steve Schwartzman

      October 31, 2013 at 8:35 AM

  4. This and the other linked species are very different in appearance. I like the white center on this one.

    I looked up spurge in iowa. Nearly all entries were for an invasive leafy spurge in about 1/4 of the counties.

    Jim in IA

    October 31, 2013 at 6:50 AM

    • One thing that makes it clear that these plants are all in the same family is their little tripartite seed capsules, one of which is prominent in today’s picture. I see them on lots of plants in my area, but some are inconspicuous and similar to one another, and which I therefore have trouble identifying.

      Spurge is just the general vernacular name for a plant in the Euphorbiacea, which is a huge botanical family. If you do a search for Euphorbia and Iowa, or Chamaesyce (another genus) and Iowa, I think you’ll find plenty of other species in addition to the Euphorbia esula (leafy spurge) that has invaded from Europe. Snow-on-the-mountain, Euphorbia marginata, is one of them.

      Steve Schwartzman

      October 31, 2013 at 8:46 AM

  5. Because this is an invasive plant we in NJ consider it an undesirable plant, might I say: weed?

    • Even some native species can be invasive, which is a way of saying that they are good at establishing themselves. Might I say that nothing succeeds—or in this case breeds—like success?

      Steve Schwartzman

      October 31, 2013 at 8:51 AM

  6. This is a beautiful image, Steve! By the way, I hope you’re not effected by the flooding in Austin.

    Alex Autin

    October 31, 2013 at 7:35 AM

    • I’m near the crest of a long rise, so there’s never any flooding up here, but some low-lying areas have been affected. You know how prone central Texas is to flash flooding: I saw on the television news a few minutes ago that parts of Hays County got 15 inches of rain!

      Steve Schwartzman

      October 31, 2013 at 9:07 AM

  7. Very pretty, but now I must dash–the mention of teeth reminds me of just how hungry I am. ! 😉


    October 31, 2013 at 5:56 PM

  8. Yes, I do sense the vague resemblance to poinsettia, and it’s amazing to see it in white. My other encounter was with the Fire-on-the-Mountain in FL, but P.R. must also have it at higher altitudes. Our Poinsettias here don’t thrive in San Juan where it’s at sea level. They fare better in mountainous areas.

    M. Firpi

    October 31, 2013 at 10:32 PM

    • I didn’t know much about poinsettias, but I found some interesting things—especially cultural and horticultural—about them in the Wikipedia article:


      I’m assuming the poinsettia is an introduced species in Puerto Rico; is that right?

      Steve Schwartzman

      November 1, 2013 at 6:08 AM

      • Oh yes, it is, and it’s done great here (Euphorbia pulcherrima). But, it will die on coastal areas; it needs the cooler air of the higher altitudes to thrive. Euphorbia dentata has not yet been recorded in P.R., however, according to the USDA site, but who knows it may be here but yet unrecorded. Euphorbia cyathophora is here, but it’s also up in the mountains.

        M. Firpi

        November 4, 2013 at 4:42 PM

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