Gunter

Seen this form before... Cuzco like but it is not a Cuzco. It is a nice form. Worth growing but spines are a pain

Might be a hybrid if seed is from a grower and not an insitu location

Not for sure but reminds me of some forms of maihueniopsis conoidea

Genotype informs phenotype. A phenotype cannot express which is not created by the genotype in response to environment. The two terms are fundamentally linked in a biological sense. The real issue for relative ID is complex. You have a phenotypic range, which is vital, but not enough to ID something as that a hybrid could express a phenotype of say a pachanoi, but be F1 and thus not a true pachanoi even if it passes as one to all observers. If only we could easily culture anthers and produce haploid specimens from our plants in question... My plant physiology teacher would say... Plants have all the anthers.

Agreed. TPC seems very tricky to ID for certain. I view any opinion on it as potentially valid be it pachanoi or peruvianus.

F latispinus?

It is synonymous with a few ferrocactus species that appear quite similar.

Echinocactus cornigerus might be something to look at.

No idea... But FYI some echinocactus species can look similar.

Nobody with any credibility or experience with these plants will have anything to do with the guy.

Zelly would likely say wild pachanoi... It is actually a matter of debate. He could be right. I classify things like the Kimnach pachanoi as peruvianus But that is me. My Icaro seedlings grew identical to my MG pachanoi and some looked like Kimnach... However it is a mess because intermediate forms between pachanoi and peruvianus exist, both as stable forms and as F1 hybrids... So something in between is tricky. Some would say pach, others Peru, and in a way both are right.

I think so

1/16 makes a noteworthy difference when speaking in terms of indoor lighting, but not an enormous difference.

Light makes a big difference in growth rate, but this might also be due to nutrients or other factors. It is hard to say.

I saw some SSO2 crosses with PC that had a few very bridgesii looking plants that did not look so much like SSO2, though they had a more intermediate spine habit with clear centrals being common. As for SSO2 X bridgesii, I believe that may have happed but never ordered or grew any. My SSO2 X SSO1 varied a bit. Not much, but a minority of them were the fastest growing plants I ever grew.