Hi Leslie –
Rust is the most common fungal disease affecting hollyhocks. While it usually does not kill the entire plant it will show up early and continue attacking new growth throughout the entire growing season. It is most often found on the surfaces of lower leaves and stems. Look for white, slightly raised spots that become covered with rust-colored spores. Eventually these spots will turn yellow and eventually black. Leaves will be deformed and drop in severe cases.
As for rust affecting your hollyhock seeds… Well, yes there is a very good chance that the seed, or other plant debris, could carry the infection in the form of fungal spores. Consider storing the seeds with a light application of sulfur or copper dust. Both are broad spectrum fungicides that will kill the spore and break the disease cycle.
I have included a link to our Rust Control page that offers several organic and natural treatments for this persistent problem.
Hope it helps!