Unknown Mushroom

Okay, now I have decided that although they are growing in the exact same location and both have white spore prints, they are actually 2 separate species, and this year they are growing in together with the one mushroom taking over the area and pushing out the other. The ones in this spotting are definitely faring better. Photo # 4 shows the small ones at the base, which are the same as the species in the spotting of October 31, 2011. Confusing cause they are growing in together. Or not??? Fungus experts help here?

Note in this earlier spotting of mine, that the stipe is whitish in the young mushroom and gets darker as it matures. This is the exact same spot! http://www.projectnoah.org/spottings/7737456 as this current spotting only taken Oct 31, 2011.