Here are two plants in bloom right now whose common name begin with “ground.” First, the ground nut (Apios americana)
This is a plant I searched for back when that’s how I tried to find edible wild plants. I would identify the plant from a book, and then go out looking for it. I never found it that way. Later, I switched to identifying what I had found, and this turned up in the backyard at the edge of the woods. It has an edible tuber, and I have eaten them on a few occasions. This is the only stand of ground nut that I know of, so I have been going easy on them. Over the past five years, they have spread by an order of magnitude, and I think that in a couple of years, I should be able to harvest them less conservatively.
The second “ground” plant is the ground bean:
The “amphicarpaea” portion of its binomial name means something like “two kinds of flowers”. These are the open flowers. The other type are closed, which may be above ground, or below ground. The closed flowers self-pollinate.
A lot of source call these “hog peanuts”, but I don’t call them that any more, as Samuel Thayer (an edible wild plant author) says it’s a racial slur against Native Americans. They used this plant as a food source, and the Europeans refused to eat them, insisting they were only fit for hogs. And by extension, by Native Americans. They were missing out on a good thing, as these beans are quite good. However, they are difficult to collect. The Native Americans let small rodents collect them on their behalf. The critters would squirrel them away in underground storage holes, and when the people found these caches, they would take half, leaving the rest for the hard-working rodents.
I have not had the fortune of finding a rodent cache of these, so the only way I can get them is by digging. The edible “beans” come from the underground flowers, and are therefore located underground. They are worth the effort though.