A title, and a plant
In Santo Daime, Rainha refers to Our Lady venerated as Queen of the Forest, Sky, and Sea, most often identified with the Marian feast of Nossa Senhora da Conceição, celebrated December 7 and 8. In Afro-Brazilian religious practice, the same figure is commonly syncretized with the Orixá Iemanjá. Confusingly, Rainha is also simply the plant name Santo Daime uses for Psychotria viridis, one of the two botanical components of its sacrament — a separate use of the same word.
The founding account
Santo Daime's own histories recount that Mestre Irineu first learned of the sacrament's two components from a man named Antônio, and that Irineu later identified both the vine and the leaf in the forest on his own. The accounts say that after an initial visionary experience taken with Antônio, Irineu underwent a further encounter in which a luminous, regal woman appeared to him and identified herself as the Queen of the Forest — understood, in the tradition, to be Our Lady of Conception herself.
According to this account, she told him he had been chosen for an important mission, asked that he observe a period of dietary restraint before their next meeting, and on a later encounter entrusted him with what the doctrine calls the Império de Juramidam — glossed by Padrinho Sebastião as combining jura ("God") and midam ("Son"). The tradition dates Irineu's founding of the doctrine to 1930, following these experiences. This is presented here as Santo Daime's own foundational narrative, not as a claim of historical or medical fact.