This winter, my lawn was suffering from an iron deficiency.
I gave it some ironite. Grass was very happy.
I had half a bag of ironite left in the garage, next to various other fertilizers, pesticides and other fun lawn/garden/household stuff.
When I'm gone on my motorcycle trip and my brother is watching my house, he doesn't realize it's pretty common for winter and spring grasses to die off once the temps start knocking at triple digits, and for the summer bermuda to resume dominance. This is usually indicated by a period of lawn browning, in May, in AZ. Give it a couple weeks and increase the water to the lawn, and things are fine.
He means well, but panics. And instead of buying a relatively harmless lawn fertilizer, he looks through what I have in the garage and decides to throw down a bunch more ironite.
I can tell from the way the grass is growing, that he didn't use the spreader, and just kinda half-arsed it by throwing it or spreading it by hand or shaking it out of the bag or something. There's wild patches where the grass that should be dormant is going gangbuster nuts.
And in the middle of those wild patches of low temperature climate grasses, reacting to the dramatic increase in iron and water... are GIGANTIC mushrooms. I wish I took pictures of them, but I shoveled them up and threw them in the yard waste bin. No stalk as far as I could tell. I giant sheet of white pasty moldy 'shroom. Almost like someone smeared a 2" thick sheet of bacon grease into my lawn. Each place where this would happen was about a foot wide by 2-3 feet long.
So, I need to make sure I cut the lawn shorter for the next month or so and let the spores that remain get lots of sunlight to burn up and die.
Anyone know what kind of mushroom or fungus this was, by the description?