"Echinocereus ferreirianus". LLIFLE. 2013-08-04. Retrieved 2024-06-29. This article incorporates text from this source, which is available under the CC BY-SA 3.0 license.
"Echinocereus ferreirianus". LLIFLE. 2013-08-04. Retrieved 2024-06-29. This article incorporates text from this source, which is available under the CC BY-SA 3.0 license.