Mushroom Plains is a mushroom type and based off Mushroom Gorge from Mario Kart Wii. The course is quite small and consists of only three quite big shrooms. Rocks often fall onto the course and rebound of the shroom making it bounce the character high into the air.
Mushroom Plains is the first world (World 1) of New Super Mario Bros. 5-Star Adventure. As the first world in most NSMB games, it is a grassland world where Peach's Castle is located. Roy is the boss here.
In the sequel,? Lemmy Koopa? is the boss, and the world also has an edition feature - a statue of a Super Mushroom located near the fortress. It can also be seen on the level it is near.