all I can find is they used to be called cyclamen neapolitanum, and the rust is called huechera rust, and I cano't beshore that hederifolium is imune from the rust ,but some one said they were.proberly no help but I tryed.

I have to say that even the Cyclamen Sociey Website offers no mention of this problem and I had never heard of it myself, It must be a failry new problem. I was wondering if someone else (besides my friend) had experienced this.

Heuchera rust is only found on heucheras, as I understand it.
it shouldnt go onto anything else
It is generally caused by a set of weather conditions or contamination from other plants.
Rust on Heucheras can be treated easily but chopping off all the leaves and spraying with roseclear 2 or anything with systhane (not sure if thats how you spell it) until the plant is all clear burn all discarded foliage and wash equipment after process also if possible scrap top layer of soil off and throw away
this is really the same route for any type of rust as it is spread by micro spores that will if allowed spread onto other heucheras.
Always keep an eye on alll your plants for any signs of rust as the soon it is spotted the easier it is to cure.

I grow a lot of these in various places but fortunately have not experienced rust, normally associated with high humidity and deficiency of potash. I have experienced rust on primroses and cowslips in the wild in the past. As I can see it the copper based spray i.e. Bordeaux Mixture may help to reduce it, in the area it is growing, not to forget spraying should be carried out several times throughout the year to control dormant spores as well as when it is attacking the plants.

From what I can gather from this grower, none of the normal treatments for rust on other plants seems to be working. It may not even be a 'rust' it just begins with a rust like spot on a leaf and then spreads. Had a look at some of my 1,000s of Cc. hederifolium and coum today and none of them appear in any way afflicted by anything like this. Having said that, the grower is a VERY experienced and expert grower and retired chemist so he really does know his stuff about prevention and cure. Hopefully it is not a widespread or going to become widespread. I will keep you all informed if I hear any more.

I have not had rust on my cycl. coum or cycl. hederifolium
I have loads in our woodland bit of the garden but never have i had rust
(having said that my woodand bit is more like a small border realy I just like to call it that) lol