Guide: Stamp 41 - Ms. Flower's flower bloomed!

How to get Stamp 41

You have to get a seed, and the way to get the seed is to get the fruit by the tree on Papaya Island, then you in turn give that fruit to somebody in White Mountain, their house is right next to the frozen pond, and they'll give you the seed.
Then you can give the seed to Flower in My City assuming you have told her about the city.