* "A Flower, a Letter": The title itself alludes to the Romantic tradition of sending flowers and letters as tokens of affection, a practice common in the 19th century. This ties the poem to the themes of love and courtship that permeate the Romantic era.
* The Garden: The poem's imagery of a garden, with its "rose," "violets," and "lilies," evokes a sense of Edenic beauty and innocence, potentially alluding to the Biblical Garden of Eden. This reinforces the theme of love's purity and the speaker's yearning for it.
* "I am like a flower/ That is waiting for the sun": This simile, while seemingly straightforward, can be viewed as alluding to the Greek myth of Persephone, who was abducted to the underworld by Hades. Persephone's return to the surface, symbolized by spring's arrival, is akin to the speaker's yearning for the love that will "bring" her to life.
* "I am like a letter/ That is waiting for a seal": This simile references the practice of sealing letters as a sign of authenticity and completion. In this context, the "seal" can symbolize the love that will validate and complete the speaker's feelings.
Overall, "A Flower, a Letter" doesn't contain explicit allusions like specific characters or stories. Instead, it uses imagery, themes, and language that draw upon broader literary and cultural traditions, creating a sense of resonance with other works and ideas.