Wingo drops Toadette under a tall tree with a river flowing by it. Go under the tree's slide and drop down the ladder into the water. Nearby, in an underground alcove is the first gem. Use the ladder to get out of the water, then walk towards the log with an Ant Trooper walking over it. Drop down near a gem you can't reach yet. There's a plant with ten coins in the corner. Climb the ladder to the log with two Ant Troopers. It's a little difficult to go through the log without being hit, but you should run quickly. Leave the log and drop down, then cross the log raft to a P-Switch. This raises the log raft up to the log at the top of the tree. Drop down into the log and you'll find the second gem. There's a hole in the log at the other side. Drop down from it to hit a P-Switch, which makes the log rotate. Drop down under the log with the Ant Trooper and walk up the ramp to the third gem. Make your way back to the rising log raft and drop into the spinning log. Drop onto the log with the two Ant Troopers and you'll find a hidden Gold Mushroom at the end closest to the raft. Return to the spinning log and drop down onto the tree's slide. Walk up the slide to the Star.
Special Challenge: Find the hidden Gold Mushroom.