[Jeff Randall]

Personally, I don't care for the edibility test taught in 21-76. For most folks, a survival situation is not going to be long-term enough to worry about having to forage for plants of unknown edibility. The next issue with plant foraging is finding enough of something that is edible without having to expend more calories than you will take in by foraging the plant. So, in short, if a particular plant is sparsely populating your area, then forget whether it's edible or not and just leave it alone. Food, in most survival situations, should be the last priority of survival. Water, shelter, navigation, signaling and the "comfort" factor of fire (even in tropical areas) all rank way ahead of food. If you're fit, then the body will go a long way and for a long time time without food, and the feeling of hunger goes away after a couple of days of moving through bush. Properly identifying plants that have good food value takes a lot of practice with someone who really knows the area and usually that knowledge comes from years of practice and "living" the skill.