Pellaea atropurpurea, commonly known as purple-stem cliffbrake or just purple cliffbrake, is a fern native to North and Central America. Brake is an old word for fern, related to the word bracken. Like many other members of the Pteridaceae, it is a rock plant, needing a calcareous substrate.

P. atropurpurea is an apogamous autotriploid, with 3n=87 (actual base number, n=29), and is one of the historical parents of the hybrid species complex, Pellaea glabella. Apogamy, or the ability to reproduce non-sexually, is common among rock ferns in the Pteridaceae.

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