Portraits of Wildflowers

Perspectives on Nature Photography


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Dodder Attacking Greenthread 6605

Here’s another first for these pages: dodder, a parasitic plant in the genus Cuscuta (there are various species that are hard to tell apart). Dodder has almost no chlorophyll, so to survive it sends out many yellow or yellow-orange or orange tendrils whose tips force their way into the stems of other plants and extract nutrients. Not surprisingly, the plants preyed upon aren’t happy about that and sometimes show their displeasure by dying.

To give you a sense of scale, I’ll tell you that each tiny popcorn-like flower you see in the photograph was only about 4mm (a sixth of an inch) across, from which you can infer how slender the dodder’s orange threads were. I’ll add that the plant being attacked here was greenthread, Thelesperma filifolium.

Like the last view, this one comes from a piece of the Blackland Prairie on Wells Branch Parkway at 10th St. in Pflugerville on May 13th.

© 2013 Steven Schwartzman


Written by Steve Schwartzman

June 5, 2013 at 6:21 AM

4 Responses

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  1. Interesting plant. I especially loved, “show their displeasure by dying.” Lol.

    Lisa Vankula-Donovan

    June 5, 2013 at 6:39 AM

  2. I just noticed dodder along some abandoned railroad tracks about two weeks ago. The tracks are edged by a ditch on one side and a marina on the other, which makes the area nice and moist. With a strong east or south wind the water will come as high as the tracks. Reading about this plant when I first came across it I learned that it likes to have wet feet – it’s obviously happy where it is.

    I’m always amazed by the force exerted by plants. It’s astonishing to me that its “tips force their way into the stems of other plants and extract nutrients.” I saw a vine this week whose tendril had encircled a new sego palm pup, about two inches from the top. It had pulled so tight that it looked as though the tip of the new growth already was dying. I thought briefly about letting it be, to see if it could actually cut off the palm’s tip, but I unwound it and sent it up a nearby wooden post instead.


    June 7, 2013 at 7:31 AM

    • Your comment reminded me of a poem by Dylan Thomas that begins:

      “The force that through the green fuse drives the flower
      Drives my green age; that blasts the roots of trees Is my destroyer.
      And I am dumb to tell the crooked rose
      My youth is bent by the same wintry fever.”

      I’ve learned that some vines, e.g. morning glories, climb on other plants merely for support. And then there are the more insidious ones, like dodder, which penetrate other plants and steal their nutrients.

      I think you once mentioned Japanese dodder, which adds alienness to the mix:


      As far as I know, all the dodder I’ve seen in Austin is native.

      Steve Schwartzman

      June 7, 2013 at 8:13 AM

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