Fungus
 

I have a small lawn at the front of my house which is now infested with
hundreds of mushroom-like fungii. There are two types, one is brown with a
flat head curling inwards at the edges while the other is white, tall with a
large narrow cap.
They first appeared at this time of year in 2001. Last year only a few
reared up - but this year they are back with a vengence.
I wonder if anybody would be kind enough to identify them for me (I have
pictures which I would happily email - they are small .jpg files) and, more
importantly, to get rid of them once and for all.
Many thanks in anticipation.