A shaggy parasol. It may have been kicked over, or perhaps some of the snails and slugs which had eaten chunks out of the cap had also nibbled away at the base of its stem.
The West Park Canada geese parents, like the swans. were left with one surviving young. Here they were keeping guard as it fed by the edge of the lake.
Giant polypores, quite a common fungus at this time of year. The fruiting bodies can get to quite a good size, and usually grow as a big cluster. But these had emerged confined between the tarmac of a pavement and a brick wall, limiting their size.