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ANNOUNCING! For the three people in the world who care…our old grass site (dating from 2004) is back online under a new url:   www.floridagrassesandsedges.net

ANNOUNCING! For the three people in the world who care…our old grass site (dating from 2004) is back online under a new url:   www.floridagrassesandsedges.net

click it here


therefore a classy grassy blog today…

Maidencane is as Smart as a Slime Mold

Panicum hemitomon  (Hymenachne hemitomon)


Slime molds are famously clever microbes. Put one on one side of a maze and a food tidbit on the far side,  and the slimer triumphantly solves the puzzle.  Sort of.  It slithers hither and thither confined by the maze, extending throughout.  Eventually the widespread exploratory portion of the s.m. encounters the morsel, so the microbe concentrates on that pathway.   Think of bees exploring for flowers, with successful foragers establishing a collective route to the sugary blossoms. That brings us to today’s “thing.”   It is incredible how spreading rhizomatous marsh plants colonize and divide a marsh into single-species patches, maybe an exclusive acre of  Knotted Spikerush here, a  plue zone of pure Pickerelweed over there.   That quilt doesn’t form overnight.  Think of all the “exploring” by creeping rhizomes like giant slime molds: all the pushing, shoving, border disputing,  poisoning,  social climbing, and jostling until it is all sorted out into the patchwork we see from the boardwalk. Some patches have deeper water longer, or more nitrogen pollution, or muckier soil, giving different species patchy advantages according to their needs and tolerances,

We are not air snorkels.

Anyhow, I have a thing for cypress swamps, and enjoyed today a nice example of patchy life under the pond cypress,  with a twist—a single species free of competitors.    Astoundingly few non-woody plants grow on cypress swamp floors. Well yea, ferns, but ferns are ferns,  and you could count the remaining herbaceous species on your toes.    The floor of a cypress swamp is a fascinatingly narrow ecological filter:   suffocating seasonal flooding, a thick layer of duff and semi-decayed  needles,  seasonal deep shade,  and dry-season drying.    In the swamp I explored today one species was the absolute ruler, but very unevenly.   Maidencane Grass can stand up to the harsh swamp tortures, but across the swamp it ranges from dense expansive lawns, to modest clumps, to scattered individuals, to none.     

Many here

A few here

Not many here! All these photos a stone’s throw apart.

Patchiness is easy to envision when forced by competitors, but in the cypress swamp there’s a different pattern.  The strongest Maidencane growth is generally where the cypress trunks are fewest.  That is, within the swamp the cypresses are subtly patchy, probably having to do with varying hydrologic conditions combined with the occasional gap from treefall.  I don’t think the water conditions are the main control of the extreme Maidencane patchiness.  Although untested, the driving force appears largely to be the relative light conditions caused by uneven cypress positioning.   The Maidencane is probably fluctuating at the edge of its shade tolerance “in exchange” for a monopoly on the swamp understory herbaceous layer. Like a giant slime mold, it spends eternity floating and creeping around the swamp, “finding the food”  in relatively bright spots and fading out when prospects dim.

 
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Posted by on March 12, 2026 in Uncategorized

 

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The Wonderful Images of Grass

Grass Family

Poaceae

A number of years ago George and John started taking a close look at the some 200 species of grasses  which are found in our neck of the woods.  This project led to spending many hours in the field collecting specimens and many hours in the lab studying the specimens.  A lot of this work was done with a loupe (hand lens) and/or a microscope since the key to a positive ID is close examination of the spikelet – the smallest readily identifiable part of the flowering part of the grass.  As the work progressed, I started photographing the spikelets.  And the more I photographed them, the more I came to love their many shapes and textures.

Some grasses have diverse “bristly” coverings and protrusions.  Perhaps most familiar to any beach goer are the nasty “sand spurs” formed by Cenchrus.  These burrs are spikelet clusters provided with wicked barbed spines.  The spine impales your toe and your toe disperses the species.  They also protect the fruit from predators, as no right-minded creature would eat these seed coverings.

Coastal Sandbur (Cenchrus spinifex)

More diverse are awns.  These are needles attached to the tips of glumes or lemmas (or occasionally to other structures).  Awns range from microscopically small to multiple inches long.  They are common in a large number of species.  The functions are diverse.  They help break the spikelet apart by catching wind, rain, or creatures.   They can help orient, lodge or embed (plant) fallen spikelets.  Some awns twist and move in responses to humidity changes, suggesting limited ability to “screw” into the sandy soil.

Coast Cockspur (Echinochloa walteri)

 

Lopsided Indian Grass (Sorghastrum secundum)

 

The plant world is full of seeds on parachutes, and  grasses are no exception.  Several species have fuzzy or cottony parachutes on their spikelets.

Sugarcane Plume Grass (Saccharum giganteum)

 

And finally one that large and flat so that it can be carried by the wind or ocean currents.

Sea Oats (Uniolata paniculata)

 

If you liked seeing these images you may enjoy this short video on the shape and texture of more grass spikelets.  http://vimeo.com/36310464

For more information on grasses, sedge, and rushes visit our website: http://floridagrasses.org/

 
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Posted by on February 8, 2012 in Grass

 

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