The speaker watches someone searching through weeds in a spring field, and then does something odd: they dissolve into the landscape. They become mud, grass, the dirt under the other person's fingernails, even bark that flakes away. It's a way of being present without being seen, close enough to be touched but never noticed as a person.
The feeling here seems to be a mix of longing and quiet frustration. The speaker is "held fast," clinging to this person, while the one they love "pass[es] on, satisfied," apparently unaware. The closing question, "do you see me here, or in the air?", turns the poem into a plea. The speaker wants to be recognized, yet has scattered themselves so widely that recognition feels almost impossible.
The mood is sensual and dreamy, full of green air, swaying branches and tongues. It also feels lonely, like a ghost haunting a place full of life. The title's word "apparition" fits that sense of being there and not there at once.