Hello all,
Here is a little Govt. sponsored write-up on PVPs. While brief, it covers
some
history. I do not agree with much the author asserts/opines, and some of the
information is out-of-date, such as fees and length of protection. These have
been
amended in the last couple of years. Just a starting point: http://www.nal.usda.gov/pgdic/Probe/v2n2/plant.html
Hope this helps,
Heron Breen
zone 4, Maine