i live in hawaii and i see this little guys when it rains, but are they all different or the same?
[submitted by @tinseltina ]
These look like mottlegills (Panaeolina foenisecii), which will pop up on just about any grassland that is regularly cut (or grazed), but not otherwise treated. They’re also frequently referred to as lawnmower’s mushrooms and haymakers for this reason. As you’ve observed, they’ll often appear on lawns after a rainy night.
What little evidence there is suggests that these mushrooms are toxic, and can cause sickness if eaten.
Panaeolina foenisecii is the type species of the relatively very small Panaeolina genus, which contains only a few species. Panaeolina foenisecii is the only one that appears in the UK, but as you’re in Hawaii, these may be a different, similar Panaeolina species.
That is - all except the second photo, which looks different. The stem and cap both appear too thick, and the cap too bell-shaped for even a young mottlegill. Although it may just be a strangely angled photo or unusual specimen, my firm guess would be that that’s a completely different species - though I couldn’t go about IDing it from that photo.