prairie turnip

Psoralea esculenta, prairie turnip is an herbaceous perennial plant native to prairies and dry woodlands of central North America.

0.4 ounces of prairie turnip or one bulb will have around twenty calories.

I am including this plant for several reasons.
First it is a perennial so like the Jerusalem Artichoke and the ground nut it can be stored in the ground.
Secondly, like the ground nut it is a member of the legume family and is a nitrogen fixer.
Thirdly, the plant is not tolerant of very high soil moisture. It likes a well-drained soil. They are good for dry conditions or well drained soils. You ground nut on the other hand likes high soil moisture. So you have both conditions covered.
Fourth, USDA hardiness zone : 4-8 so you can grow it in cold areas.
Finally, it was one of the most important will food plants of the native Americans living on the praires.

I have found one warning about this plant, warning: consuming the plant may trigger a photosentive reaction in some people, due to the presence of furanocoumarins. Furanocoumarins are the culprit behind the "grapefruit juice effect" that some prescriptions prohibit drinking grapefruit juice with that drug.

Prairie Turnip Psoralea esculenta - also known as the prairie wild turnip, Indian breadroot, and several other names. This is one of the ingredients used in our fry bread mix. The Prairie Turnip was probably the most important wild food gathered by Indians who lived on the prairies. In 1805 a Lewis and Clark expedition observed Plains Indians collecting, peeling, and frying prairie turnips. The Lakota women told their children, who helped gather wild foods, that prairie turnips point to each other. When the children noted which way the branches were pointing, they were sent in that direction to find the next plant. This saved the mothers from searching for plants, kept the children happily busy, and made a game of their work. Prairie turnips were so important, they influenced selection of hunting grounds. Women were the gatherers of prairie turnips and their work was considered of great importance to the tribe. IN 1804, LEWIS AND CLARK called it the "white apple" and their French boatmen called it pomme blanche. In 1837, while crossing the James River basin, Captain John Fremont refers to it as pommes des terres, or the ground apple. I learned it as Indian breadroot, but it's most commonly called prairie turnip. The Lakota call it timpsula.

Timpsula produces a spindle-shaped tuber about four inches below the ground. This tuber, although nutritionally similar to a potato, differs in taste and texture due to different types of sugars and starches. The white edible portion is exposed by removing a coarse brown husk. If the thin portion of the root is left attached, the tubers can be woven together into an arm-length bundle for easy drying and transport. When air dried, the tubers can be stored indefinitely.

Timpsula has been a source of food and commerce on the Great Plains for centuries. The tuber can be eaten raw, cut into chunks and boiled in stews, or ground into a fine flour. The flour can then be used to thicken soups, or made into a porridge flavored with wild berries. Mixed with berries, water and some tallow, the flour can be made into cakes, which when dried, make a durable and nutritious trail food.

Seeds can be obtained from prairie moon nursery.
This is a legume species (member of the pea family).  Most legumes harbor beneficial bacteria called rhizobia on their roots.  Prairie Moon provides genus-specific strains of this bacterium called inoculum for legume seed free of charge with the purchase of legume seed. 
https://www.prairiemoon.com/seeds/wildflowers-forbs/pediomelum-esculentum-prairie-turnip.html

Ecological and vegetative indicators of tuber biomass in Pediomelum esculentun on the standing Rock Reservation
https://www.sittingbull.edu/programs/envsci/reu/Stonefish-Ecologicalvegetativeindicatorsoftuberbiomass.pdf

Seed-Germination Studies of Psoralea esculenta Pursh (Indian Turnip) and Psoralea argophylla Pursh (Silver Scurfpea)
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=11&cad=rja&uact=8&ved=0CEwQFjAK&url=http%3A%2F%2Fdigitalcommons.unl.edu%2Fcgi%2Fviewcontent.cgi%3Farticle%3D1190%26context%3Dtnas&ei=3-dMVJT8KsqhyATSvYH4Cw&usg=AFQjCNHlw8my5KGsKainN21N6JmlRNrVSQ&sig2=1blNp8K6EHOk94UaBjOM9A