S. arachnoideum gnaphalium?

I read that there is a plant in cultivation with the name Sempervivum arachnoideum gnaphalium. I have problems finding out if this is a formally descriped form or some kind of cultivar. Any idea?

Oh, there 's a lot of mess considering that name and no answer.

Name is written in at least 6 different ways - as
- S. arachnoideum gnaphalium
- S. arachnoideum 'Gnaphalium'
- S. arachnoideum subsp. tomentosum "gnaphalium"
- S. arachnoideum subsp. gnaphalium
- S. arachnoideum var. Gnaphalium
- (or just simply) Gnaphalium

About the word "gnaphalium"
It comes from Greek word "gnaphalion", which is a name for a plant whose soft white leaves are used as cushion stuffing.
So we can say name reffers to soft white leaves ...