Virtually all plants distributed by the big players these days, e.g. Proven Winners, are noted as Patented or PPAF - Plant Patent Applied For. Strictly read, you are not even supposed to replicate the plant for your own use. "Asexual reproduction is not allowed" or some such is common phrase on plant tags.
For a variety that is patented, the patent applies to all of them.
For those granted on or after June 8, 1995, the term is 20 years. Not sure of what the status is for a 1982 patent. Expired? First Plant Patent was 1931. Lotsa info here:
http://www.nolo.com/legal-ency...
When you buy a patented plant, a fee per plant goes to the patent holder and varies - I have seen then from 10 cents to several dollars.
IANAL - I Am Not A Lawyer, but I did work closely with them for 30 years and held their hands - even writing discovery, cross examination questions and I once wrote a 287 page Brief when an attorney vanished on a project for which I was the clients consultant/Expert Witness.
