If I'm remembering correctly, these giant lily pads are called Dinner Plate Water Lilies, but it's possible I'm making that up. They are way bigger than dinner plates, as they're maybe 2.5 ft across. Even though I don't usually like taking pictures of random people and then posting them on this blog, I'm glad there are some faceless people back there to help with relative size.
This was the main stem of one plant, and then it branched out with the giant lily pads. The undersides are thorny, which I assume helps protect them from hungry fishes. The day we went it was quite windy, and a few had actually gotten flipped over. I think if we had visited Longwood Gardens one week earlier, we would have seen the lily ponds at their prime, but they were still worth braving the chilly air to see.
I hope you're having a good weekend and that the holiday season is making you merry rather than stressed out. Happy Sunday!