Peniocereus what?

[DavisK]

So far my track record in identifying cactus has not been good......0 for 2. Maybe I'm closer this time.

I think this is Genus Peniocereus, but I am at a total loss as to the species. Every time I thought I had it, either the flower petal shape (rounded ends) or the number of ribs (ten) would throw me off track. The main stem is about 4 1/2 ft. tall and as mentioned has ten ribs. The areoles are white and are about 1 cm apart. This plant is growing in a creosote bush in Phoenix, AZ.

[Minime8484]

Looks like classic Penioncereus serpentinus to me.

[DavisK]

Thanks for the reply. That's what I first thought, but every flower picture I saw showed the pointed petals. These seem to been more rounded than those pictures. Am I making to big a deal about this shape? I do that occasionally.........okay........frequently!

[Minime8484]

http://www.cactuseros.com/Detalles/Iden ... tinus.html" onclick="window.open(this.href);return false;

Looks pretty similar - I wouldn't put too much weight on that difference.

[tumamoc]

There are several species of Peniocereus that look like that, formerly classified as Nyctocereus. However, serpentinus is the most common species of that group, and most likely what you have there.

[DavisK]

From now on it is Serpentinus. Thanks for the replies. I am in the process of trying to get all the plants in my yard photographed and correctly named. I really appreciate the help. Thanks again.