#3 Euphorbia lactea cristata, AKA 'Elkhorn.' Often found grafted to another Euphorbia (E. neriifolia).

Is the second one wrinkled on one side? Just curious, if it is wrinkled, it looks concerning to me.

Planto

This post was edited by plantomaniac08 on Sat, Apr 12, 14 at 21:27

#1 is a Hoodia (not a cactus, but a succulent).

#2 looks like a Gymnocalycium.

Here are two pictures of cactus #2. Could it be due to more sunlight on one side?

smooth green side
{{gwi:535039}}

bumpy redish-orange side
{{gwi:535040}}

1.) Hoodia Gordonii
2.) Ferocactus? Looks to be variegated to me.
3.) E. Lactea Cristata

I apologize as I don't know if that one side is exhibiting something bad thing or not. It concerns me as it's a different color than the other side and it's wrinkled. Hopefully someone else will chime in. I would keep an eye on it just to be sure.

Planto

Number 3 is a Gymno. Round spines without transverse ridges. These are prone to discoloration, and if they recover it can take years. Enjoy the color it is, as long as it is not soft, it doesn't seem to affect the plant. I had a similar one turn red, candy apple red because of the cold and it remains that way. Still blooms, etc. and even has offsets.

This is a Noto with a similar problem, though not as discolored as your plant.
{{gwi:509506}}

Here's a Gymno with a rouge problem from the cold. It is this color all the time now. Offsets taken before the cold episode maintain the green color.
{{gwi:535041}}

The same plant can be seen in the back center as a greenish plant a year or 2 ago. I has a bloom sticking up, just to the right of the one with yellow flowers.
{{gwi:535043}}

Oh my, I thought I was looking at a cactus nursery for a second. ;) Let me just wipe my computer screen, I think I drooled on it.

Planto