I attempted to root from caput-medusae tubercle and set up on25/01/09. The tubercle was normal one and rooted.
I checked roots and found development of a tap root.
Although developped roots, the appearance of the top, tubercle did not change at all as below:

Since the result was not so good, I did 2nd attemption.
Pups would come out from tubercles when caput-medusae was grafted.
I cut a tubercle with a pup and set up on 09/09/09.
It seems roots come out now but no change on top.
I hope I could see some change soon ----.

Cool idea Hanazono. Hope it works out.

I was told about a method they are using in Germany at the moment with caput-medusae, where they take a section of a tubercle, cut it length ways and then graft that. Apparently it works, but the person telling me had no luck with it.

tripsis
Yes, tubercle grafting of caput-medusae is not difficult. I grafted 3 tubercles last year but I have not seen any pups yet.
Hanazono

I'm eager to give this a go since my grafted caput-medusae has thrown out quite a few new tubercles (tentacles?) this season. Hanazono, what characteristics should I look for in the tubercles if I am seeking to get pupping?

Lachy
In fact, the tubercle on the previous photo has alived but no pups has come out yet unfortunately.
I did rooting a tubercle with a pup. The plant was in flower in this spring.
I think you should select a thick tubercle for cutting.
The photo is rooted tubercle with a pup.
Hanazono

Hmm... this plant may prove to be more of a challenge than I anticipated. Here's another question then: how often does this plant offset from the tubercles?

My grafted specimen appears to be in the early stages of offsetting from where a flower grew last season:

Lachy
Offsets come out quite often from tubercles when a caput-medusae was grafted.
A flowering bud is turend to offset sometimes and an offset also comes out directry from the flowering position of the last season.
Hanazono

I forgot to attach photos.
Hanazono
1. Looks like a flower bud

2. It is turned to a offset

That's really cool. My plant currently has quite a few candidate "buds" on it like that those depicted above.

I really love this particular species. Its growth habit really has me intrigued.

Yes I have a plant that has done the exact same thing Hanazono. I tried to pull it a part to see what was inside, a month later the shoots cam out. Strange plant.