@misc{indiciae9c6197f94ad5,
  title = {George Engelmann : botanical notebook 9 : Echinocereus, Cereus, Eulychnia, Pilocereus — Illustration, [No.] 2072},
  url = {https://www.biodiversitylibrary.org/page/56136787},
  note = {Source identifier: page-56136787}
}