Naturespeak A naturalist's view of the world

December 1, 2008

A Stellar Fungus

Filed under: Uncategorized — wykes @ 10:11 pm


The Earth Star (see above) is a fungus but not a lowly one.  It can literally raise itself above the pack and move about in the manner of greater life forms. I recently encountered a constellation of these unique puffball relatives in a patch of barren sandy earth near Grand Rapids, Michigan (see here). I “captured” a few and brought them home in order to conduct a little…er, test of their motive skills.

  I am hesitant to say that I experimented with them.  That sounds way too much like the plot of an old science fiction film. I would be the aging scientist with a beard and spectacles who allows “something to go horribly wrong” after the radiation test. The irradiated fungi would grow into humanity-shredding monsters and knock over toy villages – spewing death spores over the innocents. I, the bespectacled aging scientist, would be left saying “What have I done. What have I done?” No, my test would involve nothing more than water and willing subjects.

  To our eyes these earth bound stars appear fixed into their position and for our immediate purposes this is just fine. One doesn’t need to sneak up on earth stars or view them though a telescope. This late in the season they are nearly as worn out as the beleaguered soil upon which they grow. But even in their cracked and weathered state, it is easy to see why they are called what they are. A central mini puffball is surrounded by a stellar arrangement of leathery “petals”  which gives them an otherworldly look.

  They begin their life like most fungi as a mass of mycelium in the dirt. This type, called the Barometer Earthstar, prefers to spread its fibers in thin soils where there is little competition. A small round, and multi-layered, fruiting body is formed and pushed up above the surface. Eventually the outer few layers peel back to expose a thin-walled puffball with a central opening (in the movie this would probably be the mouth!). All that remains is for falling raindrops to punch away at the exposed papery ball to release puffs of spores. This is where the thing gets interesting.

  Earthstars are not content with just sitting there in a state of blind mindless hopelessness for rain. They, in their blind mindlessness, actually seek to raise their puffball up into the lofty atmosphere. The “petals” absorb atmospheric water, or directly soak up the liquid element, and by so doing are compelled to curl even further back. This action propels the star’s punching ball center into the heavens where air currents can carry away the spore clouds. True, “lofty” in this case is only about a 1/4 inch off the ground, but this is enough to change the influence of air currents. When conditions dry up, the petals are pulled back into a shielding position.

  A fully elevated earthstar looks like some sort of a clumsy spider. See this side-lighted view (here) and you can see the ominous shadow.  Now, just for the heck of it, picture a tiny house engulfed in the shadow and terrified people running for safety. Once into position, the star is totally disconnected from its earthly connections – something that ordinary mushrooms and puffballs can’t do. But, it can’t move unless a hefty gust of wind propels it across the landscape. 

  The actual self-actuated motion takes place during the uncurling process.  This action is very slow, so it needs to be viewed on fungal time.  I’ve put together a few photos showing what happens during the water absorption period. The first picture shows a dried up star in “tuck position.” This is the same star pictured above, believe it or not. I added water to the container and within 3 minutes the petals had unfolded to the appearance of photo 2. One minute later, the whole thing had shifted position as in photo 3 and the star had reached full extension after 7 minutes.  Not bad, considering it takes some of us longer than that to get out of bed in the morning. 


I leave you to consider the amazing earth star. Oh no, what have I done?

1 Comment »

  1. OK, this is really, really cool. But it begs two burning questions:
    1) Why the heck have I never heard of these cool earthstars before? (This question is mostly rhetorical.)
    2) How the heck did you learn so much about the natural world?! (This is a serious question.)

    Comment by Monica — December 3, 2008 @ 8:16 am

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