Much like its themes the structure of the poem, A Supermarket in California, does not follow traditional form of poetic construction. It does not have a fixed rhyme scheme or stanza length.
The use of long lines in the poem is perhaps taken from Whitman’s own writing style who is invoked in the very first line of the poem. Too much transpires within the passage of a single line, also indicative of the uncontrollable rate of growth of capitalistic adventures. There is also an excessive use of exclamation marks in the poem, especially in the first stanza, this is done to indicate a sense of horror that Ginsberg feels looking at new America and to also add almost a magic realist quality to the descriptions.
The poem then can be said to be a prose poem, which is essentially a poem written in prose form and not in the verse form while preserving its emotional excess and use of imagery. Allen Ginsberg can be said to have written this poem in Vers libre that rejects the conventional norms of poetry writing like fixed meter, rhythm, pattern etc. and is a poetic form that allows flexibility. Ginsberg begins the poem with apostrophe and uses it frequently throughout the course of the poem. Apostrophe is a figure of speech where a reference is made to a person who is either dead, or not present.
‘What thoughts I have of you tonight, Walt Whitman’
‘I saw you, Walt Whitman’
‘Where are we going, Walt Whitman?’
‘and you, Garcia Lorca, what were you doing down by the watermelons?’
The largest metaphorical symbol and idea of the poem is the supermarket itself, which becomes an indicator of the new America Ginsberg belongs to. The placement of figures of the past here, using apostrophe adds a thematic contrast between the new and the old. The poem ends on two mythical allusions, of Charon and that of River Lethe.
“Charon quit poling his ferry and you got out on a smoking bank and stood watching the boat disappear on the black waters of Lethe?”
Charon is the Greek and Roman mythical figure who is the rider of the ferry which travels across the river Styx to carry the recently deceased from the living to the world of the dead, moving into Hades, the underworld. The Lethe is one of the five rivers of the underworld, the people who drank the water from this river experienced complete forgetfulness. The myth symbolizes the forgetting of the dream of the old America, and ends on a note of pessimism.