Confused Gymnocalycium

[Saxicola]

My Gymnocalycium marsoneri normally blooms all summer long on top of the plant like it should. However, recently it went through an identity crisis after watching my Rebutia krainziana bloom from base. So it decided to do the same thing! You can see the fruit on top from a normal flower. Thought I'd share the pic.

On a related note, that is my best light indicator plant. That shot was taken a few weeks ago when my late summer shade problem was beginning. Now it is almost totally green on top. In the spring and early summer I get intense sun and the entire plant is reddish orange with no green at all! Did this last year too.

[Saxicola]

Since I mentioned the light thing, here's a pic from May and one from today.

[Arjen]

that's quite the difference indeed, great that they do that!
I haven't got a clue what causes the weird flower, maybe there's a pup under there?

[iann]

Gymnocalyciums flower from the apex, although some of the Muscosemineum group do tend to produce flowers partway down the ribs. You might have a pup coming down there, or it might just be using up old areoles that didn't flower when they were at the apex.

I have a Turbinicarpus that consistently produces rings of flowers like a Mammillaria, despite a characteristic of the genus being flowers at the apex.

[masscactus]

I will speculate that is not G. marsoneri, but simply anistisii ssp. damsii.

[Tony]

I agree with Brian, my G. marsoneri doesnt change color much no matter what time of year it is, but G. anisitzi and stenopleurum which grow right beside it, both change colors rear round.
That flower is funny, I have seen G. stenopleurum produce flowers like that but it was coming from yet unseen offsets growing underneath the main plant.

[Saxicola]

Thanks for correcting the species. I'm not a Gymno expert so I was just taking a stab at the name since I got it unlabeled. I'll look at G. anistsii.

I thought about it being a pup, but I've looked as close as I can without unpotting the plant and don't see anything. I think it was just an oddball, one off kind of thing but I wouldn't complain if a pup did appear next year.

It seems like it has done well for me this year. Until I posted those pics I didn't realize it had grown so much. Maybe this time next year it will touch the edge of the pot.

[Steve Johnson]

Since I mentioned the light thing, here's a pic from May and one from today.

Wow, very nice to see the change there! I selected a Gymno stenopleurum for my collection precisely because of its attractive skin color as it responds to the sun. However, I got it just 2 months ago, so should be interesting to see what the plant looks like through fall and winter. Another similarly attractive cactus is Sulcorebutia pulchra, which takes on purple highlights when the sun is strong enough. The difference between spring and summer is quite distinct, although difficult for my pulchra to do it justice in photos with all the dense spination there.

Anyway, congrats on your Gymno, and let's see it in full bloom!