Here in my backyard in Southern California, there appears to be this relatively smooth, mottled-colored dome-like structure a little larger than a chicken egg in the dirt. Can anyone identify it? Is it some sort of insect nest or a multicellular fungus?

mottled dome in the dirt mottled dome in the dirt

Edit: After a couple weeks, I've observed some changes. It appears as though this is definitely a fungus and it has been growing taller out of the base. I also see a few feet away something that looks a little different, but not that different, which appeared even at first to be more mushroom-like. Right now the closest thing I could find online is something like a Shaggy Mane. Here are the new photos:

after two weeks, mushroom has grown after two weeks, mushroom has grown nearby mushroom

Edit #2: It's been about three more weeks, and the fungus has continued growing larger. Also I am pretty confident that the second one is also the same species. Both have been growing longer and have started to crack at the top.

mushroom after 5 weeks mushroom after 5 weeks mushroom after 5 weeks, top view of fissure mushroom #2 after 5 weeks

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    $\begingroup$ It looks like a fungus to me. It might be some sort of stinkhorn, and in that case you should see it taking form (and smell) soon! $\endgroup$
    – picapica
    Aug 9, 2016 at 20:50
  • $\begingroup$ @picapica How are you concluding what it is? Can you give more information? $\endgroup$
    – A L
    Aug 10, 2016 at 1:03
  • $\begingroup$ Hmm, I'm obviously not confident enough to post a proper answer. Just that it looks similar to mushrooms I've seen. Search for "stinkhorn egg" to see pictures of the early stage of the fruiting body. Unfortunately I don't see anything that looks just right. Have you tried poking it to see what texture it has? $\endgroup$
    – picapica
    Aug 10, 2016 at 8:32
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    $\begingroup$ understandable! but, nest or fungus, if you have it in your back yard you can keep an eye on it and see how it develops! i'm really curious, you must promise to keep us updated. another mushroom thought: perhaps some sort of puffball? $\endgroup$
    – picapica
    Aug 10, 2016 at 19:07
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    $\begingroup$ @picapica I'll probably add a picture. I think it looks a little like a shaggy mane mushroom, something like Coprinus comatus or Coprinus narcoticus. $\endgroup$
    – A L
    Aug 21, 2016 at 22:24

1 Answer 1


This fungus is known as a puffball, although that is no longer a taxanomic order. Some of these fungi don't have small openings through which the spores disperse, but they burst open when the spores are ripe. This proces can be clearly seen in your last pictures. The brown stuff below the cracks are the spores. I think when you press it, the brown stuff will come out

Looking at the appearance, I think this is a Calvatia, but as I am unfamilair with the American fungi I can't name a species.

  • $\begingroup$ Is there anything else I should know about it? Should they be removed, are they edible? Does it vary? $\endgroup$
    – A L
    Sep 19, 2016 at 19:32
  • $\begingroup$ It varies. Some are edible when young, but yours isn't any more. I see no reason to remove it. $\endgroup$
    – RHA
    Sep 19, 2016 at 19:33
  • $\begingroup$ OK thanks. But wouldn't leaving them cause more to grow? $\endgroup$
    – A L
    Sep 19, 2016 at 19:34

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