"Faces in the Crowd" (line 1)
The first line depicts as unnatural a setting as possible – a crowded subway station. Nowadays, people go on hiking and camping trips to get away from things like the subway. The people in the subway don’t even seem to have bodies; they are just anonymous "faces."
"Petals on a wet, black bough." (line 2)
The second line fuses the image of the chaotic and stressful world of man to a peaceful and intense vision of a flowering tree. The first line is kind of vague and imprecise, but the second line puts the reader right there with nature. It has simple words that appeal to the senses, like "petals," "wet," and "black." These words even sound tangible, like one could reach out and touch them.