Some of these food sources are frequently NOT recognized by most people, hence they may remain available in a wide spread disaster situation where more recognizable foods are picked bear.
http://www.offthegridnews.com/off-grid-foods/10-wild-off-grid-foods-you-can-forage-for-each-fall/Some of these are either native to our local region (Nevada) or have been imports in past years. Some are region specific an may not grow in your climate.
Sadly, not enough pictures are in the article, but a short websearch will show you what to look for in each plant.