Hi Cristi,
You are correct. The flax for eating is Linum usitatissimum. Linum usitatissimum does grow wild though in your area(see the link below,) so hopefully you can aquire the seeds from someone.
Remy

Here is a link that might be useful: Linum usitatissimum Info Page on Missouri Plants

Wow,
great site! Thank you very much, I have added it to my bookmarks.
Photos were taken in Columbia and I will be there working for a few days this week. I will drop in at the conservation center and see if they can help me =)

thank you Remy!