Hello, went nursery hopping yesterday and my FIL picked out a cactus. I will need to cactus sit for a couple weeks. I know absolutely nothing about cacti!

Could someone please share some care tips with me? It is labeled Color Top Cactus. I will post a picture.

@abhege can you post a picture of the cactus?

This will be easy to care for; water VERY SPARINGLY.

Just found out this is actually Two cacti! Unfortunately the top one does not like direct sunlight like the bottom portion. So I have moved it out of the window to a bright indirect light area. Whew!

Thank you for the info Hetty.

Top is a cactus, bottom is a Euphorbia, usually.

Bottom should be dragon fruit type. A forest type cactus which can take more water than normal. Top is a greenless desert cactus which likes it very dry. With no green, it depends on the bottom to deliver it's food. It does look so simular to the Euphorbia lactea used to graft crests onto. Don't have the exact name of the dragon fruit. Sorry.
Stush

Ah, you're right Stush. Makes total sense.

Yeah. I bought one. Ripped the top off and threw it away after it would not root. Now I have a dragon fruit with 3 branches - longest ~ 2 feet - in ~ 4 months. hylocereus.

Most of mine rot off due to me over watering it. The top cactus can't live on it's own because it has no Chlorophyll to make food with. That's why they have those bright colors, just like fall leaves on the trees. There is a new one out there that has a rainbow of colors in them including green and black and does live on it's own. Expensive right now. They will come down. Found two Black/yellow ones at K-Mart of all places for only $3 each. And I bought only one. How stupid.

Stush2019 said: Top is a greenless desert cactus which likes it very dry. With no green, it depends on the bottom to deliver it's food.
Stush

How the heck does that thing survive? It is not born atop the other? [ scratches head]

The colored cactus is man-made and grafted (fused) to the green cactus (stem). The stemmed cactus makes the food for the colored portion.

Hence, when separated, the color portion dies. It cannot produce its own food.

Man made? Gymnocalycium cultivar is man made? Or do you simply mean than man makes them by grafting Gymnocalycium cultivar on to Hylocereus undatus?

The odd colored ones (yellow, pink, orange, red) are man made.

And technically the grafting of the two cacti is man made too. You physically have to graft them together (they just don't appear like that).

Opinions differ then - Merry Christmas

Of course! Isn't that what makes us different?

Merry Christmas!

I think they first appeared after atomic bomb testing and found they can't live on their own. They must have been on green stock cactus and later removed onto some thing more common and cheap.

Back to ground zero?

Not sure what's going on here. I didn't post that a second time.