Swollen Bladderwort

Swollen Bladderwort

 

Horned bladderwort

Horned bladderwort

The surface of the sphagnum mat on Rye Pond was yellow last week with the blossoms of a bladderwort (probably horned bladderwort, Utricularia cornuta).  This is one of several carnivorous plants that grow in the bog.  Bladderworts typically have small “bladders” under water that trap tiny aquatic organisms.

The trap mechanism is remarkable.  I will allow Wikipedia to tell the story:  “In the active traps of the aquatic species, prey brush against trigger hairs connected to the trapdoor.  The bladder, when ‘set’, is under negative pressure in relation to its environment so that when the trapdoor is mechanically triggered, the prey, along with the water surrounding it, is sucked into the bladder.  Once the bladder is full of water, the door closes again, the whole process taking only ten to fifteen thousandths of a second.”   The prey is digested at leisure (which usually means within a few hours).  The water in the bladder is pumped out through the cell walls and the trap is reset, sometimes in as little as 15-30 minutes.

I live on a small pond that is full of bladderwort.  The feathery foliage rarely reaches the surface unless a piece breaks off.    I swim over it gazing down through my snorkel mask into a jungle of fronds where one of the most sophisticated traps  in the plant kingdom is at work.

Last week I found an old friend – one I first met only last summer.  I have canoed on many ponds in the region for the last 40 years but never saw this plant until I took to swimming with a mask.

ImageThis is the “swollen bladderwort”, Utricularia inflata.  A star-shaped structure, usually five- or six-rayed, rises on a stalk from the plant below.  It looks like a piece of exquisite white lace.  This “star” must contain air, for it pulls the stalk below straight up as a balloon would.  A thin stalk rises from the center of the rosette topped by a small yellow flower that reaches within a foot of the surface.  I can’t photograph this so you’ll have to be content with a photo from the Peterson  Field Guide to Wildflowers – or go find it yourself!   As I was, you will be surprised by beauty.

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