ID for some unusual cacti

[Stillman]

I have a few cacti in the collection I'm not sure of hoping someone might know what I have.

I never seen these two before?

1

2

Trich species?

3

4

and a possible Gynocalycium denudatum hybrid or strain the flowers look like they may be yellow on this one.

5

[Cereusly]

1.)?

2.)Tephrocactus sp. Probably articulatus

3.)?

4.)in the back Myrtillocactus geometrizans on the right Pachycereus marginatus

5.)?

[bℓσωηG]

1st one could be a Mamillaria of some sort ,does it have turbicles?

[TheExplorer]

3 kind of looks like a Trichocereus spachianus.

[Stillman]

Thank for that guys I found out the Gymno too it wasn't denudatum but another species which I can't remember at this point but has a really cool lemon flower.

[Jonstn]

1st one could be a Mamillaria of some sort ,does it have turbicles?

 

That's what I was thinking looks like a younger version of one I got

[zelly]

first pic- I'm guessing copiapoa species