E. oxygona is a good grafting stock for Astrophytum, Ariocarpus and many others, although I've never tried to graft O. brasiliensis, as it grows very well on own roots. For practice you can graft any globular common cactus on E. oxygona. For grafting thin pads or forms like Schlumbergera, you'd have...

I agree, this is G. anisitsii.

Regards
Alex

Hmmm... a very long grown Parodia nivosa?

Regards
Alex

Echinopsis rhodotricha ssp. chacoana

Good job!
Was this grafted on Selenicereus?

Regards
Alex

Frailea and Astrophytum can germinate in 48 hours, others may last longer.. Most seeds should have germinated within 2 weeks.

Regards
Alex

Good job, but I think you'll need a light source!

Best regards
Alex

Hob. I've just seen your flower closeups. They are stunning and very beautiful!!

Best regards
Alex

Selenicereus is a great stock for Gymnos.

Regards
Alex

Is Graham perceived as a lumper? I think so! :-) Well, there remain always a lot of mysteries, regarding this! Only one example: G. fleischerianum is newly considered a form of G. paraguayense, but both grow at a very little distance, without hybridisation. This is a very important fact to consider...

This is for me a G. anisitsii/damsii form. G. marsoneri/megatae has grey/bluish flower stems.
Of course, it could be also a hybrid between of some of the above!

Best regards
Alex

@Jens, your plant labelled as fricianum seem to be a form of G. anisitisii. G. marsoneri/megatae/tudae are a completeley other group from another habitat type and different flowers and fruits. In respect of the cold tolerance of the Chaco-Gymnos, I can tell that there could be some nights with light...

1 and 2 could be M. vobournensis.

Regards
Alex

Hi Jens, I've visited some G. anisitsii/damsii habitats. The "rotundulum" comes from south east Bolivia, where the air is much more humid than in central Chaco (mihanovichii). All these forms are doing well in my collection in a hot and humid ambient with a light shade in summer. I'm water...

That looks interesting! I suppose you cut off the long spines before grafting...

Please keep us updated.

Regards
Alex