Marvell is considered to be one of the last Metaphysical poets as well as one of the best. These lines are proof of that. They are very similar to some of Donne’s poems. Marvell talks first about massive oceans and then condenses things down to ‘green thoughts in a green shade’.

The Norton Anthology of English Literature, Ninth Ed., Vol. B The Sixteenth Century/ Early Seventeenth Century.

Footnote to these lines: “Apollo, the god of poetry, chased Daphne until she turned into a laurel (the emblematic reward of poets); Pan pursued Syrinx until she became a reed, out of which he made panpipes. The gods' motives were, of course, sexual, not horticultural.”

In the footnote, the last line points out that Marvell’s technique here is to confuse the motives of these gods. In the poem it is presented as if the gods pursued the women in order to obtain them in plant-form, and by doing so, reap the poetic and musical rewards that these plants signify. There is absurdity in this assumption, encouraged by Marvell, which points out again that, when the pursuit is of love, or of nature, the symbolic (which has its role in poetic language) does not do justice to capturing these things.

Marvell seeks out a perfect correspondence between language and object, between signifier and signified.