Mary's Response to "Washington Etude"

I think Elizabeth Alexander wrote a poem about suppression. "...Mushrooms appear in the park but you cannot eat them...", "...clear, sweet drops. I am a hummingbird."
and reference to a cat lapping cream (not milk) from a bowl suggest consumption of delicacies known to those who are privileged. By gender or race, yet again, duality,is eluded to, in the eighth stanza, where she says, "'''white...black-..." Interesting that the eighth stanza refers to opposite 'colors'(neither one is considered a color).
The ninth and tenth stanzas, "...Buttercups under my chin tell me all I need to know..." suggests much is assumed of her, as is, what do buttercups under her chin look like in comparison to another, or to "...other children playing outside my window..." "...Nothing blue occurs naturally in Washington, someone says, and I believe it..." suggest to this reader she is alluding to a reality she cannot prove, having not at this point in her life [perhaps] yet seen for herself.