Id please its very difficult

Hello!!
Id please
Formosa, chionocephala,orcuttii....the identification of these plants I find difficult.
Thanks.

I think orcuttii is quite distinctive with its black spines and radials that soon drop off, and I think your first photo is of that species. As for the others.....

Well, M. formosa would probably cover them all depending how broad your idea of what a species is! My plants of this species are now just coming into flower, and I would say that your last one looks very much like a plant named as M. eumorpha which was described fairly recently but has been around for a while. I'm still trying to make sense out of all the names and now have about 35 of them, with various collection numbers, and names from arroyensis to brauneana to caerula to ritteriana ......

Sorry for not answering before Chris.

The first was that clearer had, though he doubted sometimes because some pictures confounded me, tapeworm and as orcuttii and remains so.

the second and third I have no idea of the species, the more I look the more I mess that could be, internet sometimes instead of helping more disorienting.

the fourth tapeworm as formosa ssp pseudocrucigera but equally doubtful.

the fifth at first thought in chionocephala, but the flower spination and make me doubt much, maybe it's you mention Chris.

Thank you so much for everything and especially for the quick response.

Anyone is encouraged with some opinion more?

regards