When Olimar or a Pikmin stands on top of one's petals, it goes down with the weight. After a while of being under the pressure, the petals spring back up and throw whoever was on top directly upwards. The more weight that is being put on it, the more it springs back, which also results in the passengers being thrown farther up. Dots appear above the flower to represent how much weight is being put into it. Every time a new passenger is placed on top of it, the time left until it springs back is reset, which means that the player can add more weight at their own pace, so long as they don't wait too long. The trick in using these plants is knowing just how much weight to put onto them such that the passengers get sprung up to the desired height.
Names in other languages