Long (sprawling?) cactus ID

[MoonB]

Hello everyone, I'm new here but I've been perusing the site and love all the great info After much searching I just can't seem to ID this cactus growing in the yard of the house I moved into. As you can see from the photos it varies in size but I can't tell if it's considered shrubby or sprawling and no blooms. It looks like so many other species so you can see why it's been difficult to identify especially for someone not well versed in this field. This is a fairly big lot with LOTS of trees, plants, etc. so I've been avidly trying to identify what I've got Any suggestions are much appreciated. I look forward to learning more about cactus and succulents through here!

IMG_5086.jpg (202.65 KiB) Viewed 1063 times

IMG_5087.jpg (346.73 KiB) Viewed 1063 times

PS-I'm in S. Tx bordering Northern Mexico if that helps. Not sure if it's native for just planted by the previous owner.

[toadstar]

It could be a type of Selenicereus.
http://cactiguide.com/cactus/?genus=selenicereus

[vlani]

Harissia may be?

[DaveW]

Agree with Vlani that it may be a Harissia. See:-

Click on pictures to enlarge them.

http://cactiguide.com/cactus/?genus=harrisia

[MoonB]

Thanks for the suggestions everyone. I've been looking through these but also Cereus and many look alike to me. Now my question is, what's the difference between Harrisia and Cereus? I search one online I get results for the other. I didn't mention it earlier or get a clear image of the top but the cactus has 4 ribs. I've tried searching that way too but can't seem to find anything.

[DaveW]

Cereus is a genus, but sometimes the term Cereus or Cerei are used as a collective term for all the similar tall thin cacti, therefore a Google search for "Cereus" will often both bring up the genus itself plus other Cerei, or plants of similar habit to the genus Cereus.

I would say it does not belong to Cereus the genus, but more akin to the other Cereoide genera already suggested.

As to difference between Harrisia and Cereus, I believe Harrisia has hairs in the scale axils on the flower, but Cereus does not, but I may be wrong?