Mushrooms? In /my/ plant?

[nonethefewer]

Hokay.

* The visual dictionary's entry on a mushroom.  Another image.  (Also one in Japanese.  ?)
* A-ha!  A fantastic resource on mushrooms.  Go to the end for images.  This is useful for...
* ...RogersMushrooms.com.

So:

- Convex, fibrous cap.  [eta] Could be conical.
- It has gills underneath, same colouring.
- Cream-coloured, with a dusky tip on the cap.
- Bulbous end to the stem ("end" = "just before it goes underground").  Actually, club-shaped, apparently.
- The ring is flared, just one.
- The stem is... I can't find my ruler, but it's neither spidery-thin nor chunkily-huge.
- The stem is currently not longer than the cap is wide, from what I can see.
- It's straight up, not off the side or weirdly diagonal.
- There's just the one - no clustering (yet, at any rate).

Also, a new picture.  It's still a bit blurry, but you can see most of what I described above in that image.

Probably a reeeally common type, but I know dick about mushrooms, so.  The links above are useful for knowing names and identifying marks, but are less so for narrowing down what this one is.

?????

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Edited-to-add notes:

- The cap is vaguely rubbery.  The edges are tending to curl.