Davide,

I eagerly await a positive ID on the second - I have one also and have never been able to figure out what it is. It just seems very "soft" and too bunchy to be a cereus.

Sorry can't help with the mamm either.

Yes, the first one is a Mammillaria :)

The second one is Cereus tetragonus, a very popular monstrose form.

Davide-

Those are beautiful olive trees in the background of the second picture. Do you harvest the olives? This spring I hope to acquire a nice Manzanillo or Sevillano tree.

cd

The first one looks a lot like Mammillaria knipelliana, but it has no axilary wool.
And the second is Cereus tetragonus
Alfonso

I was going to offer M. mystax, although a couple others come to mind. Its a shame that the plant in perfect focus is the little tiny one at the back :)

Like an extra
Andrerson do not make any reference to this name in his book. Mammilarias .net has it like a synonim but do not mention from whom.
And garden-tropicals from where I take the name has an error in the name, must be M. knippeliana not knipelliana.
This is the one that I have like M. knippeliana
{{gwi:461820}}
Alfonso

I'd bet a paycheck that the first one is M. mystax. Here's mine:

{{gwi:461821}}

Amy

Thank you all for your help!
cd: Yes I grow about 300 olive trees, The trees were all planted by spanish people during their domination here in Sardinia about 300 years ago. Some of them are huge and here you can see how I have to harvest the plant that I didn't prune.....
{{gwi:461823}}
ciao
Davide

Wow! That's a huge tree. Which varieties do you grow? I just finished reading a book about the history of olives, their cultivation, and the oil making process. The olive truly is a noble tree.

cd

cd: It's a "oliva bosana", a typical variety of our zone.
ciao
Davide