Dickinson turns an overflow of feeling into a problem of money. In eleven short lines, the speaker admits to having "So much Summer" and wonders whether giving away even "a Smile's minute" would be "Too exorbitant." The second half turns to a wealthy "Lady / With the Guinea" and a tiny offering, a "Crumb of Mine" so small that "A Robin's Larder" could hold it. The central idea seems to be the awkward arithmetic of generosity. How do you hand over something precious, or admit to having it, when it looks so slight beside a rich person's gold?
The grammar is knotted, so any paraphrase is a bet. One plausible reading is that displaying so much Summer would be improper ("Illegitimate"), so even a brief smile might seem an extravagant price. The speaker then turns to the Lady and says, in effect, *look*: if she knew what the speaker really has to give, she would see how little it is. "Summer" can stand for warmth, joy or inner richness, but the poem never says which. The Lady is also unnamed, so she is safer to treat as a figure in a small allegory than as a portrait of a real person.
The poem's most striking move is to translate feeling into the language of commerce. "Illegitimate" belongs to law and inheritance, "exorbitant" to bills and overcharging, and "bestowing" to formal, ceremonial giving. A guinea was a British gold coin, so the Lady carries the standard measure of value. Against that stands the speaker's wealth, which is made of seasons, smiles and crumbs. Judging by the imagery, the contrast is between money, which is minted, counted and kept, and natural abundance, which is perishable and can't be handed over in a purse. Because the speaker keeps using the vocabulary of accounts, even a smile starts to feel like something with a price.
The poem also shrinks as it goes. It opens with a whole season, narrows to a single minute of smiling, then to a crumb, and ends in a bird's pantry. Each step is smaller and more domestic than the last. The "Robin's Larder" is a playful touch, since it gives a bird a household storeroom and makes the speaker's treasure comically tiny. It is also humble and rather charming. The speaker may be apologizing, or may be quietly claiming that this small, natural economy is worth as much as the Lady's coin.
The form supports this. The lines are very short, often only three or four syllables ("Me for showing," "Too exorbitant"), so the voice sounds clipped and hesitant. The longest line, "Would a Smile's minute bestowing," is the one about giving, as though bestowing a smile took longer than it should. The very next line, "Too exorbitant," shuts like a door. The rhymes are sparse and uneven. "Showing" and "bestowing" chime softly across the first stanza, "Illegitimate" and "exorbitant" only half-rhyme, and "know" and "stow" close the poem with a small, dull click. The long Latinate words stand out against the plain ones nearby ("Crumb," "Look," "stow"), which makes the speaker's cautious, formal worry sound a little absurd beside the homely picture of a bird's cupboard.
Dickinson's usual habits work hard here. Capitals turn Summer, Smile, Lady, Guinea and Robin's Larder into characters or objects with weight. The dash after "Look" works like a nudge, an appeal to the Lady's attention. The final dash after "stow" replaces a full stop and leaves the thought hanging, as if the speaker has offered the crumb and is waiting to see if it will be accepted.
The poem matters because it shows how much Dickinson can pack into so little. She lived in Amherst, Massachusetts, and saw very few of her poems printed in her lifetime, yet the compression here is typical of the way she writes. Missing connections and bent syntax force the reader to finish the thought. A poem about shyness and giving ends up being about reading too: you have to decide whether the crumb is an apology, a boast or a gift. That uncertainty is the point, and it is why the poem repays a second and third reading.