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False-Foxgloves and the Angle of the Dangle (revisited)

05 Sep

Agalinis linifolia and close kin

(Agalinis translates roughly as “much flax” because the foliage resembles flax, having linear (linifolia) leaves.)

Orobanchaceae, a family of parasitic plants


In the places where the mud is ankle deep lives a pretty wildflower, or should I say a few, as there are about 17 lookalike Agalinis species in Florida, perhaps three in our immediate area.  They are tall, thin, delicate and attractive, not to mention partly parasitic, swiping nutrients from neighbor’s roots.

Agalinis by John Bradford

The flowers have a weird life history, possibly not 100% true, yet documented for Agalanis species in other regions and seemingly applicable locally.  Each flower lasts only a day or less,  so hurry…get pollinated!  

  

by JB

The blossoms open early in the morning, releasing pollen before the pollen-receiving stigma is ready to go.  Any bee who happens along picks up that fresh pollen and takes it to a different flower ready to receive.  This delay holds the door open to cross-pollination as opposed to self-pollination, the ultimate form of inbreeding. Spoiler:  Selfing may follow.

The long light violet dohicky is the style, the stigma at its tip. The pollen-filled anthers are horizontal at the top of the entrance.

As the day progresses the originally short style grows and grows while its stigma tip becomes pollen-receptive.  The style attains a ridiculous length, bending down across the entrance to the flower so that an incoming bee must push under its stigma-tip and dust it with pollen to access the interior.

No bees today?  No problem…then comes backup:  The style ultimately grows into the shape of a J curling up under the pollen-releasing anther.  With luck gravity may drop pollen from the anther onto stigma tip curled under it.

Corolla dragging pollination.

Last chance to pollinate.

But a pollen sprinkle is iffy, and the flower has an even better finale.  Late in the day the petal tube and attached pollen-shedding anthers begin to drop free.    The hooked style is attached to the plant, not to the tube.    As the funnel-shaped tubes begins to  fall, its inner anthers slide past the hook, maybe even snag on it.  The passing stigma scrapes pollen from the anthers and/or mops pollen out of the narrow end of the funnel.   Wind motion may help the scouring process. Another name for the petal tube is the corolla, and this type of last-ditch self-pollination is called “corolla dragging.”    On other species of Agalinis dangling in the wind can last an hour.

It worked. Fruits.

 
2 Comments

Posted by on September 5, 2020 in Agalinis, Uncategorized

 

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2 responses to “False-Foxgloves and the Angle of the Dangle (revisited)

  1. Barbara Levy's avatar

    Barbara Levy

    September 5, 2020 at 12:46 pm

    Really looks like a smaller, fuzzy Digitalis! And I bet it’s deer resistent too!

     
    • George Rogers's avatar

      George Rogers

      September 5, 2020 at 1:24 pm

      You Barbara…they are related…used to be in the Scrophulariaceae together until DNA shattered that family…probably toxic, but if I were a deer I would not want to venture where it grows.

       

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