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Geastrum saccatum

Geastrum saccatum

Thanks once again to Robert Klips (Orthotrichum@Flickr) for sharing one of his photograph with BPotD (original via the BPotD Flickr Pool). Much appreciated!

Though these may appear to be acorns rapidly fired into small bits of cookie dough, they are actually the fruiting bodies of the rounded earthstar, Geastrum saccatum. Geastrum literally translates to earth star, and the genus has a cosmopolitan temperate and tropical distribution. Geastrum saccatum contributes to that broad range, as it is the most widespread species.

As Robert explains in his comments on Flickr, earthstars resemble puffballs when the fruiting bodies first begin to develop. As it matures, the outer skin (outer peridium) splits and peels back, forming the star pattern. In some species, the shape and length of the segments of the outer peridium are enough to elevate the inner spore sac away from the ground, but in the case of Geastrum saccatum, the fruiting body remains relatively flat and close to the ground (or as Michael Kuo describes in a linked article above, the spore case "sits directly on the arms, as though in a bowl (without a pedestal)".

Geastrum saccatum is a saprobe, gaining its nutrients from dead or decaying organic matter.

No, it's not edible.

15 Comments

Troy Mullens commented:

Very cool

Meg commented:

Thanks so much for including fungi. They are so fascinating!

Lynne commented:

I laughed when I saw your description (acorn shot into cookie dough) because just before I read that, I saw the photo and thought to myself "Huh? Was someone getting a bit too creative with the acorn-based Christmas ornaments?" Too bad it's not edible, because it looks like it should be!

Love the fungi. Thanks!

phillip commented:


"there's the wheels to my Tonka truck"

Martha Blake-Adams commented:

Love the description and the translated name of earth star! A few years ago I photographed a little colony of these in my back yard in North Carolina....I had never seen them before. Fascinating....thanks for the information and photo.
I would be happy to send my photo if you tell me where....

Bonnie commented:

Thought someone dropped some buttons on the way. :-)

elizabeth a airhart commented:

si fi its raining out the earth star opens and moves our hero is gone

the earth star saga starting next week

you tube has a fine time lase film of earth star- herbarium usu edu
has an animated earth star- arkive etc and a type of bromeliad
is named earth star -----thank you all

Hollis commented:

Neat photo! and thanks to elizabeth for leading me to the following:

Fun Facts About Fungi
Utah State University Intermountain Herbarium
herbarium.usu.edu/fungi/funfacts/factindx1.htm

joan commented:

This is so fantastic! I found something like this in our garden this fall but only one? Amazing!
joan

mary wilson commented:

As an ER physician, I'm always interested in the toxin..Anybody know which class of toxins they contain?

Aida commented:

Love it! My friend, Heidi, and I would often encounter these in our hikes through the Carolinian forests of Southern Ontario. We knew than when we encounter these, the backpacks came off and prepped for close-up photography; half an hour later and perhaps satisfied that we had gotten our desired shots, we would leave gratified that we had seen something special. Thanks for posting.

Rebecca commented:

Thank you! I have been seeing these in one area in my yard and did finally realize that they were some sort of fungus but now I know what they are! Ours are much darker though. Do you know how long each one lasts? There seems to always be one when I pass that way.

Elham commented:

really unparalleled! brilliant creatures!
and fully agree with Meg saying "Thanks so much for including fungi. They are so fascinating!"

onlyheaven commented:

I, too, am interested in knowing what toxins the Geastrum saccatum contains. Also, does anyone knows what the GS is used for since it's not edible?

Malcolm commented:

GS are great little puffballs but whatever you do, don't eat them. I'm pretty sure they're toxic.

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