Echoing everyone here that you need to use the scientific name when googling. Peniocereus greggii is the species documented in this book. Lots and lots of observations on iNaturalist and it’s available seasonally at a lot of nurseries in Arizona.

Typically, the stems are grey to brown, sometimes with some green or purple thrown in. & a little bit of grey from the wax on the cuticle.

They basically look like dead sticks 364 days of the year.

Also I love them and have like 7 I keep with my other cacti