Trying to Get an Handle on Scorpion Tail

30 Jul

Heliotropium angiospermum


Scorpion Tail is a native mystery, easy to find but tough to understand distributed in South Florida, South Texas, the Caribbean, and South America. Gardeners like it for its delicate charm.  The ancient Mayans used it in formulations against gastrointestinal infections.

Scorpion Tail by John Bradford. Look—every flower makes a fruit. One flower open at a time.

What I find remarkable is its precision.   Along that “scorpion tail” inflorescences the flowers are lined up perfectly by age, the youngest at the tip.   Toward the base they are post-opening and get older, with only one flower open along the entire wand, the ones further out being all buds, and the ones toward the base all being developing fruits.  


The flowers are visited by butterflies but not much.  I have it in my butterfly garden at home, and I never detect a visit there, despite scores of butterflies lighting on other flowers all day long.    There is “no way” every Scorpion Tail flower receives a butterfly visit. [Note added after this blog incubated. My friend and native plant expert Dane Boggio mentioned seeing a Cassius Blue on one recently, and we looked at several Scorpiontails in Lake Worth 8/7/2021. While we watched, a number of honeybees visited, as did one small Hairstreak (?) butterfly. Dane and a reader comment below caused me to suspect that I may have overstated the rarity of butterfly visitation, all depending on what is meant by “rare.”]

Yet every flower forms a fruit.    That suggests self-pollination, and various botanists have surmised selfing in varied species of Heliotropium.   But who knows…the floral biology of H. angiospermum has never been studied, so let’s be pioneers and take a stab at it.

The open flower looks normal enough, with a ring of five well separated pollen-making anthers around the opening inviting a butterfly to do what the birds and the bees and the butterflies do.

A tale of two flowers, one big and open, the other above the open one) clenched.

The next day is more interesting.  The flower does not merely close, but the petals clench in tightly like a clenched fist.   Cutting open such a clenched flower shows the anthers (white line in photo) now mashed together, the broad but short mushroom-shaped stigma (black line) below them.  Perhaps significantly,  alongside the stigma is alongside a brush of hairs (red line).   Looks to me like pollen might fall into those hair, while the flower is open or later, and then the clenching upon closing might push the hairs up against the stigma like a pollen paintbrush.

White=anthers (make ppollen). Black = stigma (receives pollen). White = pollen paintbrush?

Hmmmmmm…it might work that way (or not),  and we’ve had a fist peep at a question nobody has explored to date. Call it a working hunch.


Posted by on July 30, 2021 in Uncategorized


10 responses to “Trying to Get an Handle on Scorpion Tail

  1. theshrubqueen

    July 31, 2021 at 4:20 pm

    The clench concept means the butterflies can’t get at the tasty stuff?

    • George Rogers

      July 31, 2021 at 9:30 pm

      Presumably not after the flower closes. Their window of opportunity for any given flower seems narrow, probably 1 day, but during the day there is always 1 flower open per wand, so there is always some flower open.

  2. Paul Rebmann (@WildFlPhoto)

    August 1, 2021 at 12:25 pm

    I was surprised to read that your scorpionstail is not much visited by butterflies. We have had a number of white peacock butterflies around the yard lately and they seem to be mostly visiting the scorpionstail flowers.

    • George Rogers

      August 1, 2021 at 3:15 pm

      in which county?

  3. Uma Bhatti

    August 2, 2021 at 9:16 am

    Wow. Tiny flower has so much to learn. Thanks

  4. Christen Mason

    August 2, 2021 at 10:04 am

    Interesting that you rarely see butterflies visiting the scorpion tail in your yard. I have it in my yard and at almost any time of day I can see a butterfly on it. The large majority are peacocks but sometimes zebra longwings also. And other insects routinely use it as well – native bees, flies and honey bees.
    I wonder what accounts for the difference? Mine is grown from seed that I collected in the Biscayne Bay area of Miami-Dade county.

    • George Rogers

      August 9, 2021 at 9:01 pm

      Thanks Christen…received feedback from a few readers about more butterflies than I suggested (and from one reader who said he never saw any). I truly do not see visitors to it in my yard, but did in Lake Worth yesterday south of here. I wonder if the farther south you go, the more you see, then again my garden has as one border I-95, not exactly prime butterfly habitat.

  5. John Ward

    September 4, 2021 at 7:04 pm

    Hi George, I live in Tavares and have tons of various small bees on mine. The White Peacock butterfly just loves these flowers. That’s the main larger butterfly that visits but I’ve had Skippers also. I’ve learned not to say something isn’t possible with plants. I think our microclimates create wildlife miracles. Thanks for the article. Very interesting about the flowers.

    • George Rogers

      September 10, 2021 at 6:49 pm

      Thanks John…that is truly good to know.


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