@misc{indiciaeeae09f352f29,
  title = {George Engelmann : botanical notebook 9 : Echinocereus, Cereus, Eulychnia, Pilocereus — Illustration, [No.] 2101},
  year = {1869},
  url = {https://www.biodiversitylibrary.org/page/56134335},
  note = {Source identifier: page-56134335}
}