I'm sure this question has been asked a trillion times, but here goes...
How do I go about separating the little ones from around the mother? Wait until they are about 2" - 3" tall first? Then try cutting them away without scraping up the mother too much, getting as many roots as possible with each one?
I would wait and do this in the spring, or summer months.
They can be removed fairly early. I have found that if you sit any unrooted 'pups' on the surface of a pot they will quickly root down. Sometimes this can be easier than trying to separate roots. Let them get some size but not too big. If you get in early enough it's normally as simple as grab and gently pull. Just don't over water them while they are rooting down stick with a limited watering.
On the other hand you could let them get a decent size and then bare root the lot and separate that way. Once they get pushed for room though they often loose their shape and will contort to fit whatever container they are in.
An elephant never forgets....... I forgot what the elephant remembered...
I will wait for the pups to get larger. as long as they can keep a decent shape, then pot them all up into one small pot until they again grow larger. I just wasn't sure how difficult prying them away from the mother might be, good to know it should be a piece of cake:)
I saw some one do it with some strong paper cut into strips but not sure if you can get the strip around one of the pups to tug it out. They were doing it on a fairly tall lean one to separate it. The paper was being used like clamp so they did not get spines. Maybe bubble wrap might work to pluck them out
I use a small plastic pot big enough to fit over the main plant, rinse as much soil off as possible and attack from underneath where there's less spines. You can use a long knife to help pry or cut where necessary.
The names suggested don't ring a bell, so here's another photo of the whole cactus. Although it's in a south window, it REALLY needs to be pushed up more toward the window.
The top would get somewhat elongated during the summer months, but then the rest would catch up. This is the longest the top has even been. There needs to be some serious moving around!
After seeing the whole plant I feel more confident that it really is a Parodia magnifica (or Notocactus/Eriocactusmagnificus if you prefer). If it grows like that in summer - yes, then you really need to relocate it ... I first thought it had been growing in winter.
You are probably right about the temperature, my plant did not flower until I was able to give it a cooler winter rest (on an isolated windowsill). I like the flowers of this species, they often open even when the weather is cold and cloudy, sometimes they remain open at night too.
Yes, but it would probably have been bought as a Notocactus today as well, the sellers usually keep the old genera names in their lists (I can think of several reasons for that). Currently, Echinopsis, Parodia, Rebutia and Eriosyce (of the genera I am familiar with) are often split up in subgroups.
It's not just cacti though, I've worked in Nurseries for ages and it takes a long time for name changes to be accepted and made. This adds to confusion when books and especially garden magazines pick up new names and you end up with either a seriously confused customer or salesperson.
I understand it will probably make it easier for i.d. in the future but as the changes take place it can be a bit of headache.