Read “in a station of the metro,” by ezra pound. the apparition of these faces in the crowd; petals on a wet, black bough. in this poem, pound is comparing “faces in the crowd” to petals that are laying against a tree branch. drowning in the rain. withstanding a storm. floating through the night sky.

In this poem, Pound is comparing "faces in the crowd" to petals that are laying against a tree branch.
This is exactly what he says in the poem - "petals on a wet, black bough." A bough is the main branch of a tree, so this is definitely the only appropriate answer in this case. He wants to say that people resemble these petals.

Bbecause if the reader doesnt like vondermoot then it won’t be a seamless story