Aosta

Sempervivum arachnoideum and Sempervivum monatnum are native to Aosta valley, Italy.

You can read an interesting article about Aosta valley in Italy here:

http://www.infpro.com/hd/blattform/westalpen/exkursionsprotokoll.pdf

Sometimes you can read the habitat name as "Valle d'Aosta" - "valle" is Italian for "valley" - so this is Italian name for it.

S. arachnoideum grows in Aosta valley at elevation of 1.200 m above sea level.

Also S. grandiflorum grows there at the elevation between 2.200 and 2.800 m.

I have a plant labeled as:
Sempervivum grandiflorum
Epinel, Val di Cogne 1400m , Aosta, Italia

Collector is Cees van den Wittenboer, NL (CW 8605)

Valle d'Aosta is the name of a relatively small region in NW Italy. In the past this was a province, with the same boundaries.
In the case of Semp. grandiflorum from Epinel, Val di Cogne, Aosta (AO), Italia, it gives us the information that this particular plant was found near Epinel, which is in the Val di Cogne, which is in the region/province of Valle d'Aosta, which is in Italy.