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Forked Bluecurls

29 Jan

Trichostema dichotomum

Lamiaceae

John and George took to the scrub today in Seabranch State Park near Hobe Sound, Florida.  Sunny but nippy The recent rains have made the lichens soft, the spiders hide, and scrub plants grow new “spring” basal growth.    The only two species showy-flowery today were American Nailwort and Bluecurls.   Both are pretty little curiosities.  The Bluecurls is showier, so it gets to glory.

tricho protruding stigmas

Bluecurls.  The style (longest unit in the curled cluster, shaped like a fish hook, upper right) greets the bee first. All photos today by John Bradford.

Handbooks generally describe Forked Bluecurls as annual, and no doubt it is often, but possibly not the whole story.    Today new growth was rising around the bases of last year’s stems, growing from deep taproots, making the plants at least in today’s experience what I’d call scrub perennials, several species there behaving identically.  Forked Bluecurls seems remarkably lightly studied, given its good looks.    Most Trichostema species live in the arid West, and have received more attention there.  So now hear this:  today is interpretative and based on the botany of other Trichostema species.    This is my speculative extrapolated “take,” not established fact.

Beyond the coloration, the outstanding attribute is a set of long curled (pollen-making) stamens and one  longer (pollen-receiving) style reaching out the front door of the flower.   The outreach may seem an obvious adaptation to dust  pollen on the back of a bee, but there’s more to think about.    First of all, why the bee’s back?   The bee does not have a back-scratcher, and can’t remove the pollen burden.

And why the long down-curled configuration?   Here is how an observer in the 19th Century described the similar flowers in California Trichostemas:

Trichostema Meehan

See the bee CLICK (on similar California Trichostema)

Early when the flower is open, the stigma (pollen-receiving organ) sticks out just a little more than the stamens.    Makes sense—pick up incoming pollen from the arriving bee before depositing new grains on it.  True of many flowers. Okay then.

But as the flower ages, the stamens and style continue curling inward into a position where bee-pollination can’t happen.  Self-pollination has been reported in our local species and in other Trichostemas.   I think, and this parallels many other plants, the severe incurling represents a back-up mechanism, plan B, self-pollination after giving the bees first dibs.

tricho leverage

The calyx (green cup below the blue petals) has the back edge raised.  The flower can bend to greet the bee but it can’t bend back.

Trichostema is an appealing mint, complete with a pleasing minty fragrance to the fuzzy-sticky leaves.   Some mints share a trick with likewise strongly bilateral orchids…twisting their flowers 180 degrees, called resupination.   The Bluecurls flower looks like an orchid  (or vice versa if you are not an orchid chauvinist). Trichostema twists in an unusual way with apparent unusual “purpose.”

The calyx (small green cup around the base of the flower) has five triangular lobes on its rim:  three together and long, and two together and short.   (In most mints the three long are on the floor side of the horizontal calyx and the two shorter ones at the roof side.)

When the blossom is at its early peak for pollination it stands nearly vertical.  The three long calyx lobes stand behind the blossom as the bee approaches, forcing the blossom and the curling sex organs to bend forward onto the bee as it rests on the dotted landing-lip.    Those three tall lobes, like fingers behind a basketball in a freethrow force the action forward.

tricho late marked

Late flowers.   The stamens and styles are curled into an embrace, presumed self-pollination.    The calyx in the red circle recently lost its petals; the three long calyx lobes remain erect in back.  The older calyx in the yellow circle has the three lobes now repositioned into the diving board position with the seeds about to take the leap.

Then their role and position changes.    After pollination, the blue petals drop away leaving the calyx containing four “seeds” (nutlets).   To keep these from falling out prematurely, and to give them a springboard (almost literally) at the right time, perhaps when a raindrop strikes, the cupular calyx twists 180 degrees relocating the three long calyx lobes to the doormat position and the two short lobes as an awning over the door.   The seeds roll out onto the 3-lobed diving board.

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4 Comments

Posted by on January 29, 2016 in Uncategorized

 

4 responses to “Forked Bluecurls

  1. Laure Hristov

    January 29, 2016 at 11:50 pm

    Wow, how pretty! Awesome photos, thanks for sharing.

     
    • George Rogers

      January 30, 2016 at 1:06 am

      Thanks Laure, Looking forward to the class visit

       
  2. theshrubqueen

    January 30, 2016 at 10:20 am

    I wish I had seen those, went in search of Lupines at Hawk’s Bluff yesterday, no luck.

    Do you think the Bluecurls are reseeding biennials, that is how my Beach Sunflowers are behaving or is that a result of unfortunately timed pruning? I do have a zillion Sunflowers seedlings I am transplanting all over the garden. Maybe a happy gardening accident?

     
  3. George Rogers

    January 30, 2016 at 10:44 am

    The sunflowers sounds like about as happy as an accident can be. The bluecurls are reseeding. I an’t say they are not biennials, but the way they rise from that old root, I’m going to guess, repeat…guess, that their approach is to “build root while the building’s good” then die back to the root as season/weather/fire forces. It is amazing how un-studied this species seems to be.

     

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