Keep in mind that dessication does not mean the use of dessicants. It just means drying out the seed to the point where it can be frozen without damage. Most seeds of ornamentals that grow in temperate climates can be frozen. Trees with fleshy seeds such as chestnut, oak, maple, etc. cannot be dried or they will die.
Attached is an article that I wrote about lily seed storage. I know from personal experience that you can germinate lily seeds that are over 30 years old if you use this method. It doesn't involve dessicants or cryogenic freezers or anything high-tech, just an ordinary deep freeze. Last year I germinated some dust-like seeds of Ramonda and Haberlea that were over 15 years old.
Also, dry storage in the freezer does not count towards stratification or vernalization time. For a seed to break its cold dormancy, it needs to have absorbed moisture, and it needs to be around 40 degrees F (in most cases). To absorb moisture, it is often necessary for a seed to be in moist potting mix at a warm temperature (say 65F) for a couple of weeks, before the cold period begins. Some seeds have a tough time absorbing moisture at 40F.
