Need help identifying this seedling

[Driller64]

I grew this seedling from a cactus seed mix from Dunecraft. A bunch of them germinated, only to have many of them perish due to a fungal outbreak. This was one of the survivors. This cactus is very special to me as it was my first attempt at growing cacti from seed. I believe I have identified one of the other survivors as a Cereus due to its columnar growth habit, but I'm having trouble identifying this one. It is around two years old now, and my guesses are either a Saguaro or an Echinocactus.

[Kamos]

Echinocactus grusonii ??

[adetheproducer]

Yeah I'd agree with that, echinocactus grusonii.

[greenknight]

I'll third that. Don't like the looks of that potting soil, though; I think it needs more grit added. See the Cultivation forum for more info.

[CactusFanDan]

I disagree, looks like Carnegiea gigantea - Saguaro. E. grusonii seedlings are stouter and have a different aerole structure.

[Rod Smith]

I disagree, looks like Carnegiea gigantea - Saguaro. E. grusonii seedlings are stouter and have a different aerole structure.

Agreed. These are very common in packets of mixed cactus seed.

[adetheproducer]

I would agree with CactusFanDan, much more experienced than me. I am only a novice at this stuff.

[greenknight]

I've mistaken Saguaro seedlings for E, grusonii before - easy to do when they're this small. The difference becomes obvious when they're older.

I stand by what I said about the soil, though.

[Driller64]

Well it did say it had Saguaros and Echinocactus in the seed mix, so both of those are possibilities. But CactusFanDan is experienced, so I will just go with what he says for now. Yay, I got another Saguaro!

[Driller64]

Also another thing I've noticed with C. gigantea seedlings is the very long spines in comparison to E. grusonii seedlings, which have shorter spines. I bring this up because I did a graft of a Lophorphora seedling onto a spare seedling from that same seed mix that the subject of this thread is from so I wanted to make sure it was E. grusonii because the graft would have been useless on a slow growing cactus like C. gigantea.