This article is from the Fat-free Diet FAQ, by artemis@rahul.net (Michelle Dick) with numerous contributions by others.
As long as you eat a varied non-junkfood diet (whether
non-vegetarian, vegetarian, or vegan), you will most likely get all
the EFAs you need. But, if (for whatever reason) you would like to
consume more, the number one best vegetarian source of both EFAs is
flax seeds. However, whole flax seeds are not usually digested
well by the body and linolenic acid is very unstable and goes
rancid quickly. You should either use cold-pressed flax seed oil
that is no more than 3 months old, or freshly ground flax seeds.
In either case, eat them raw. Some like to add ground flax seed to
their breakfast cereal or to make a vinaigrette with flax oil and
add it to salad.
 
Continue to: