They are usually called "scales" or "bracts". Ovary is so deeply inside. That is flower tube, vintage line drawing or engraving illustration.

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Size: 5000px × 2524px
Photo credit: © Patrick Guenette / Alamy / Afripics
License: Royalty Free
Model Released: No

Keywords: art, black, bracts, cactus, drawing, engraved, engraving, flower, flowers, illustration, line, sepals, transition, vector, vectors, vintage, white