Linum ustatissimum is the recommended one. Don't know about the others.

Linum usatissimum (the common flax). The edible part is the seed which is incredibly nutritious, especially in Omega-3 fatty acids and lignans. I've been told never to eat any other part of the plant, which suggests there may be a problem with toxicity in the green parts, but I haven't been able to verify that to my satisfaction yet. I buy flax seed at Wild Oats, both brown and golden varieties, and grind a tablespoon or two up everyday and sprinkle on salad or mix with a little soymilk and cocoa powder and use that as a topping on blueberries.

Immature seed pods can cause poisoning. Overdoses cause respiratory distress and paralysis. Make sure that the oil you use is not the one used by artists or in preparations for timber maintenance. The seeds must be crushed, or the body cannot access the nutrients/medicinal virtues.

If you've got a good natural health food store in the area, you could probably bring a flower of what you've got in and ask if it's the right one. Maybe you can even get them to show you different ways of preparing it?

Linseed oil gets rancid extremely fast. It is best to buy the seeds whole and use a dedicated seed grinder to grind your daily portion. Eat the whole seed. The benefits are much greater that way. The recommeded dose is 4 tablespoons a day, not all at once, if possible.

Whole seeds keep well. Ground seeds or the oil have to be kept frozen. Just in the fridge is not good enough.

The same is true for wheat germ oil.

I feed 1/4 of ground up flax seed to the horses each day. I grind it up daily for them in a coffee grinder. It is unreal how it has given them manes/tails and better feet. If you want to do it in bulk a blender is great for that too. Fresh flax seed smells nutty when is ground up and fresh. You can buy flax seed at some feed stores in bulk or better yet a place that sells it for birds. I buy mine from 10 to 25 lb bags of the brown or golden seeds. At health food stores it is normally ground up meal/not freshly ground.

I guess the flax made the more "regular" too I wonder if that is a good or bad thing when having (raising) horses...... ? :)