Hi Dan,
The best reference for veggies is not online, It is the book 'Seed to Seed' by Susan Ashworth. Online, I will Google specific plants hoping to find info. I'm not sure if there's a good online all around reference site. Of course doing a search of this forum or asking if no answer is found after searching usually works : )
Remy

Ditto on Remy's recommendation. I would also add the book "Breed Your Own Vegetable Varieties", by Carol Deppe.

Of the online seed saving references I've come across, this is one of the best. Dr. McCormack's information (most notably on the use of barrier crops) has been instrumental in establishing my own seed saving program.

Here is a link that might be useful: Saving Our Seeds

I've been looking for the same kind of referance, either on-line or off. I like "Seed to Seed," but it's limited to veggies - I'm mainly a perennial/ornamental gardener and alas, there doesn't seem to be a good ref. for us.

My veggie garden is a little 10' square. I have two 200 foot fence-lines of border-beds that I'd like to harvest ornamental seed from.

ABQ Bob,
I did forget about The Seed Site in my first post! They do have a lot of great info there.
I think that there is no good reference book is because it would be too vast and complex to complete. With vegetables there is pretty much a set list of genera that we grow and so it easy to quantify and explain. With flowers it is an unending list! I know a heck of a lot about seed saving, but I still learn new stuff all the time.
Remy

Here is a link that might be useful: The Seed Site