echinosum wrote:
Looks more like a 'Shaggy Inkcap' to me.

'Rogers Mushrooms - Coprinus comatus Mushroom'
(http://tinyurl.com/7pqetxh)

Some of those photos look similar, with the more open parasol shape top,
but I don't think it is. No veil on the stem, and the not so open photos
just didn't look right.

It's a not a photo I could possibly identify a fungus from, but I think
Leucocoprinus birnbaumii is the most likely.

Not from the photos he
http://www.rogersmushrooms.com/galle...erresult. asp
Definitely white-to-brown, not yellow.

There are one or two species particularly noted for growing in plant
pots etc. Leucocoprinus birnbaumii 'Plants & Fungi: Leucocoprinus
birnbaumii (plantpot dapperling) - Species profile from Kew'
(http://tinyurl.com/6v4wx58) is the best known. They aren't always so
obviously yellow as that one, eg 'Leucocoprinus birnbaumii, aka Lepiota
lutea, the yellow houseplant or house plant soil mushroom, Tom Volk's
Fungus of the Month for February 2002,' (http://tinyurl.com/7vs8a)

None of those photos looks the right colour or shape.