This song was formerly known as "Dancer" but Animal Collective re-titled it as a result of The Killers' recent "owning" of that particular word on "Human."
Dave "Avey Tare" Portner told the French magazine VoxPop why this is the opening track on Merriweather Post Pavilion: "We used the tour to test these new songs, and naturally, we always played 'In The Flowers' at the start. It was therefore said that this piece would make a good opening on the album. Its construction is perfect for this: the slightly quiet atmosphere at the beginning and then the explosion in the middle. And then the fact that the album opens with the somewhat "complex" melody, with the feeling of deconstruction, it forces the listener to attention."
Who writes a song about a name they found in a phone book? That's just one of the everyday things these guys find to sing about. Anything in their field of vision or general scope of knowledge is fair game. If you cross paths with them, so are you.